Systems and methods using an ultrasonic transducer and scrubbing horn motion to seal a part

ABSTRACT

A system includes a first horn, a first ultrasonic transducer, a second horn, a second ultrasonic transducer, a memory, and a controller. The first horn includes a first part-interfacing surface. The second horn includes a second part-interfacing surface and is positioned relative to the first horn such that a part to be welded can be positioned between the first and second part-interface surfaces. The controller is configured to cause a first ultrasonic energy to be applied through the first horn via the first transducer to cause the first part-interfacing surface to vibrate, cause the first horn to move in a first direction at a first time, cause a second ultrasonic energy to be applied through the second horn via the second transducer to cause the second part-interfacing surface to vibrate, and cause the second horn to move in a second direction at the first time.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/888,212, filed on Aug. 15, 2022, which is a continuation-in-part ofU.S. Pat. No. 17,403,653, filed on Aug. 16, 2021, entitled “Systems andMethods Using an Ultrasonic Transducer and Scrubbing Horn Motion to Seala Part, which is granted as U.S. Pat. No. 11,426,946, which is acontinuation-in-part of U.S. patent application Ser. No. 17/074,252,filed Oct. 19, 2020, entitled “Systems and Methods Using MultipleSynchronized Transducers to Finish a Part,” which is granted as U.S.Pat. No. 11,090,758, which is a continuation-in-part of U.S. patentapplication Ser. No. 16/863,662, filed Apr. 30, 2020, entitled“Ultrasonic Welding Systems and Methods Using Dual, Synchronized Hornson Opposite Sides of Parts to be Joined,” which is granted as U.S. Pat.No. 10,807,314, the entireties of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

Certain types of packaging or containers can have complex sealinterfaces with a varying number of layers to be sealed along the sealinterface. The seal in some applications must be hermetic, air tight, ormust contain a liquid without any leaks. Conventional techniques to sealthese interfaces are extremely wieldy, expensive, and can requiremultiple passes over the same interface to complete the seal, requiringa lengthy amount of time for each item to be sealed. Some preparation ormanipulation of the item and/or its seal interface must also be carriedout before the seal can be formed. These preparations or manipulationscause additional delays in the sealing process.

Typically, these items can be composed of or coated with a plastic filmor a polyethylene material (e.g., liquid paperboard), such as pillowpacks, flow wraps, and cartons or other containers, such as milk cartonshaving so-called gable tops. To seal these items, conventionalapproaches can require different machines to seal different materials,take a relatively long time and can require multiple passes to create aleak-proof seal, suffer from inconsistent seals and can produce failedseals that produce channel leaks, produce waste, are incapable ofaddressing certain seal shapes, particularly narrow seals, and require alot of maintenance due in part to their complexity and number of movingparts.

In traditional ultrasonic welding, one ultrasonic stack is energized,and the part is pressed between the stack and a stationary anvil. Forcertain applications, this single-stack configuration poses challengeswhere the parts have multiple layers or other unusual geometries, andcan require multiple passes over the same part to create a high qualityseal or weld.

Gable top or other packaging sealing applications having an unevennumber of layers (such as 4-2-4-5 layers across a width of an interfaceto be sealed) exemplifies the inadequacy of using a single-stack horn.Suppose each carton layer absorbs or attenuates about 10% of the appliedultrasonic energy/amplitude. By the time traditional welding getsthrough 4-5 layers, there will only be about 50% of the ultrasonicenergy/amplitude remaining at the last layer, which is not enough toproduce a reliable seal. If the force or amplitude or time wereincreased to compensate for this energy loss, there is a risk ofover-welding the 2-layer section and possibly burning the externalsurface leaving a visual artifact on the product.

Round or oval interfaces, like spouts or ports, are very challenging toseal using conventional ultrasonic welding techniques. Usually,conventional techniques require many horns (e.g., up to four) andmultiple repeating movements of the horns, e.g., three steps or more) toseal these types of parts. These configurations are bulky, complex, andintroduce delay into a manufacturing process by having to repeatultrasonic movements multiple times to carry out their welding orsealing task. A need exists, therefore, for a solution that solves theseand other problems. Aspects of the present disclosure are directed tofulfilling these and other needs using ultrasonic energy in a one-passapplication to create a seal on a part, such as on a Gable top of acarton.

Parts made of metal can be deformed using a die to contort the metalinto a desired shape. Examples include wire drawing, deep drawing,rolling, extrusion, and forging processes. Some conventional processesleverage an externally applied lubricant to the die-part interface tofacilitate the deformation of the metal through the die. Conventionalprocesses can leave artifacts on the surface of the metal deformed by adie, and the throughput of the forming process is a function of thespeed and force with which the metal can be deformed as it is forcedthrough the die. A need exists to provide a better solution for metalforming processes.

Pillow pouches or bags or similar containers can be made of a flexiblematerial such as plastic or a non-woven film, polyester printed toaluminum then laminated to polyethylene, metal including aluminum, metalfoil, fabric, film, polyethylene-coated fiberboard or liquid paperboard,and the like. When presented on a roll, the sections between adjacentpouches need to be sealed to securely contain the contents of the pouchor bag. Conventional processes typically seal the pouch and later cutthe section between adjacent pouches to singulate the pouches. First,these dual seal-then-cut actions introduce latency to the throughput ofthe entire pouch assembly and sealing process. Second, the roll must bepaused long enough for the seal to be made between adjacent pouches, andthe throughput is a direct function of how quickly the seal can beformed. Speeding up this sealing process will increase throughput.Carrying out the sealing and cutting operations simultaneously ornear-simultaneously will further increase throughput.

SUMMARY OF THE INVENTION

According to some implementations of the present disclosure, a systemincludes a first horn, a first ultrasonic transducer, a second horn, asecond ultrasonic transducer, a memory, and a controller. The first hornincludes a first part-interfacing surface. The first ultrasonictransducer is configured to impart ultrasonic energy into the firsthorn. The second horn includes a second part-interfacing surface. Thesecond horn is positioned relative to the first horn such that a part tobe welded can be positioned between the first part-interface surface andthe second part-interfacing surface. The second ultrasonic transducer isconfigured to impart ultrasonic energy into the second horn. The memorystores machine-readable instructions. The controller includes one ormore processors configured to execute the machine-readable instructionsto cause a first ultrasonic energy to be applied through the first hornvia the first transducer to cause the first part-interfacing surface tovibrate back and forth along its length. The controller is furtherconfigured to cause the first horn to move in a first direction at afirst time relative to the part to be welded. The controller is furtherconfigured to cause a second ultrasonic energy to be applied through thesecond horn via the second transducer to cause the secondpart-interfacing surface to vibrate back and forth along its length. Thecontroller is further configured to cause the second horn to move in asecond direction at the first time relative to the part to be welded.

In some implementations of the system, the first part-interfacingsurface of the first horn includes a first curved part-contactingportion and a second curved part-contacting portion, the first curvedpart-contacting portion and the second curved part-contacting portionbeing configured to aid the first part-interfacing surface in engagingthe part to be welded.

In some implementations of the system, the first part-interfacingsurface of the first horn includes a first part-contacting portionhaving a first angle and a second part-contacting portion having asecond angle, the first part-contacting portion and the secondpart-contacting portion being configured to aid the firstpart-interfacing surface in engaging the part to be welded. The firstangle and the second angle can be between about 1 degree and about 5degrees.

In some implementations of the system, the first direction is differentthan the second direction. For example, first direction can be oppositeto the second direction. The control system can be further configured tocause the first horn to move in the second direction at a second timesubsequent to the first time; and cause the second horn to move in thefirst direction at the second time.

In some implementations of the system, the first direction is the sameas the second direction. The control system can be further configured tocause the first horn and the second horn to move in a third direction ata second time subsequent to the first time.

In some implementations of the system, the controller is configured tocause the first ultrasonic energy to have a first frequency and a firstphase and the second ultrasonic energy to have a second frequency and asecond phase. In some implementations, the first frequency can be thesame as the second frequency and the first phase can be the same as thesecond phase. Alternatively, the first frequency can be the same as thesecond frequency and the first phase can be different than the secondphase.

In some implementations, the first frequency is different than thesecond frequency and the first phase is different than the second phase.The first frequency and the second frequency can be about 20 kHz and thefirst ultrasonic energy has a first phase and the second ultrasonicenergy has a second phase that does not match the first phase. The firstfrequency can be about 20 kHz and the second frequency can be about 35kHz and the first ultrasonic energy has a first phase and the secondultrasonic energy has a second phase that does not match the first phase

In some implementations of the system, the system further includes afirst booster positioned between the first horn and the first ultrasonictransducer; and a second booster positioned between the second horn andthe second ultrasonic transducer. The system can also include a thirdultrasonic transducer configured to configured to impart ultrasonicenergy into the first horn; and a fourth ultrasonic transducerconfigured to configured to impart ultrasonic energy into the secondhorn. The system can further include a third booster positioned betweenthe first horn and the third ultrasonic transducer; and a fourth boosterpositioned between the second horn and the fourth ultrasonic transducer.

In some implementations of the system, the system further includes athird ultrasonic transducer configured to configured to impartultrasonic energy into the first horn; and a fourth ultrasonictransducer configured to configured to impart ultrasonic energy into thesecond horn.

In some implementations of the system, the first horn includes aplurality of slots formed along a major surface of the first horn, andwherein the second horn includes a plurality of slots formed along amajor surface of the second horn, each of at least some of the slotshaving a length running in a transverse direction to the length tofacilitate the movements of the first horn and the second horn,respectively.

In some implementations of the system, the first horn includes a thirdpart-interfacing surface opposite the first part-interfacing surface andthe second horn includes a fourth part-interfacing surface opposite thesecond part-interfacing surface, wherein the first ultrasonic energycauses the third part-interfacing surface to vibrate back and forthalong its length and the second ultrasonic energy causes the fourthpart-interfacing surface to vibrate back and horn along its length, andwherein the controller is further configured to cause the first horn torotate about its longitudinal axis and cause the second horn to rotateabout its longitudinal axis such that the part to be welded passesbetween the first part-interface surface and the second part-interfacingsurface or between the third part-interface surface and the fourthpart-interfacing surface.

In some implementations of the system, the controller is furtherconfigured to cause the first horn and the second horn to rotate whilethe first ultrasonic energy is applied to the first horn and the secondultrasonic energy is applied to the second horn.

In some implementations of the present disclosure, a method includescausing a first transducer to impart a first ultrasonic energy to afirst horn to cause a first part-interfacing surface of the first hornto vibrate back and forth along its length. The method also includescausing a second transducer to impart a second ultrasonic energy to asecond horn to cause the second part-interfacing surface of the secondhorn to vibrate back and forth along its length. The method alsoincludes causing a part to be welded to move between the firstpart-interfacing surface of the first horn and the secondpart-interfacing surface of the second horn. The method also includescausing the first horn to move in a first direction relative to the partto be welded at a first time. The method also includes causing thesecond horn to move in a second direction relative to a part to bewelded at the first time.

In some implementations of the method, the first direction is oppositethe second direction. The method can also include causing the first hornto move in the second direction at a second time that is subsequent tothe first time and causing the second horn to move in the firstdirection at the second time.

In some implementations of the method, the first direction is the sameas the second direction.

In some implementations of the method, the first ultrasonic energy has afirst frequency and a first phase and the second ultrasonic energy has asecond frequency and a second phase. In some example, the firstfrequency is the same as the second frequency and the first phase is thesame as the second phase. In other examples, the first frequency isdifferent than the second frequency. In some such examples, the firstfrequency is about 20 kHz and the second frequency is about 35 kHz.

The above summary is not intended to represent each implementation orevery aspect of the present disclosure. Additional features and benefitsof the present disclosure are apparent from the detailed description andfigures set forth below

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an ultrasonic welding system for sealing togethermultiple layers of a part.

FIG. 2 illustrates a pillow pack and the number of different layers tobe sealed along its ends to create a hermetically sealed package.

FIG. 3A illustrates a carton in various configurations showing thenumber of folds needed that creates the multiple layers in the Gable topof the carton.

FIG. 3B illustrates a close-up view of the top of a Gable top showingthe different layers present along the width, height, and depthdimensions of the Gable top.

FIG. 4A illustrates an example ultrasonic welding stack having dualhorns positioned directly opposite one another defining a gap betweenwhich the part is inserted to seal all the layers together.

FIG. 4B illustrates the ultrasonic welding stack of FIG. 4A with thehorns closed together. For ease of illustration to show the horns, thepart to be sealed has been removed from between the horns.

FIG. 5A illustrates a dual-stack setup configured to perform a“scrubbing” welding action using synchronized ultrasonic energy appliedthrough a respective horn of each stack.

FIG. 5B is a cross-sectional view showing respective side weldingsurfaces of two horns abutting one another to seal a part interposedtherebetween using synchronized ultrasonic energy applied through bothhorns simultaneously.

FIG. 5C illustrates an example configuration for carrying out ascrubbing-type welding action using synchronized ultrasonic energyapplied to opposing horns simultaneously.

FIG. 5D illustrates the same configuration shown in FIG. 5C except withthe two horns spaced a distance apart to receive in the gap therebetweenan interface of a part to be sealed or joined together usingsynchronized ultrasonic energy applied to dual horns simultaneously.

FIG. 6A illustrates another example configuration to seal or join aspout or non-flat structure to a part using synchronized ultrasonicenergy applied to dual opposing horns simultaneously.

FIG. 6B is a top, perspective view of a top welding surface of a bottomone of the horns showing a grooved pattern corresponding to a spout ornon-flat structure to be joined using synchronized ultrasonic energyapplied to dual opposing horns simultaneously.

FIG. 6C is a front view of the two horns shown in FIG. 6A having a part,such as a spout, inserted between an opening that exists between the twohorns when they are pressed against one another.

FIG. 7 are example waveforms of ultrasonic energy applied to a first anda second horn, which waveforms are synchronized in frequency and phaseaccording to aspects of the present disclosure.

FIG. 8A is an illustration of a front view of dual rotary-hornconfiguration, whose frequency, phase, and angular speed is synchronizedto weld or seal layers of a part, such as being composed of a non-wovenmaterial, together.

FIG. 8B is a rear view of the dual rotary-horn configuration shown inFIG. 8A.

FIG. 9A illustrates an ultrasonic-assisted metal wire drawing processingusing multiple, synchronized ultrasonic transducers.

FIG. 9B illustrates an ultrasonic-assisted metal deep drawing processusing multiple, synchronized ultrasonic transducers.

FIG. 9C illustrates an ultrasonic-assisted metal extrusion process usingmultiple, synchronized ultrasonic transducers.

FIG. 9D illustrates an ultrasonic-assisted metal forging process usingmultiple, synchronized ultrasonic transducers.

FIG. 9E illustrates an ultrasonic-assisted metal rolling process usingmultiple, synchronized ultrasonic transducers.

FIG. 10 illustrates example vertical form, fill and seal (VFFS), andhorizontal form, fill and seal (HFFS) packaging systems in which any ofthe ultrasonic welding systems disclosed herein can be incorporated.

FIG. 11A is a perspective view of an ultrasonic-assisted “cut and seal”assembly having dual ultrasonic transducers applying synchronizedultrasonic energy to a horn by using a “scrubbing” motion to seal one ormore interfaces on a part. Alternately this horn arrangement can beoperated with a single transducer and two boosters or a singletransducer and one booster providing cantilevered support.

FIG. 11B is a side view of the ultrasonic-assisted cut and seal assemblyshown in FIG. 11A.

FIG. 11C is a perspective view of the ultrasonic-assisted cut and sealassembly shown in FIG. 11A with the part arranged between the horn andthe anvil.

FIG. 11D is a perspective view of the ultrasonic-assisted cut and sealassembly shown in FIG. 11C with the part pressed between the horn andthe anvil to simultaneously form two sealing interfaces on the part.

FIG. 11E is a side view of the ultrasonic-assisted cut and seal assemblyshown in FIG. 11D.

FIG. 11F is an enlarged side view of the ultrasonic-assisted cut andseal assembly shown in FIG. 11E to show the two sealing interfacesbetween the horn and the anvil, and the blade inside the anvil cuttingthe part to singulate the forward part from the remainder of theadvancing roll.

FIG. 12 is an illustration of a finite element analysis (FEA) of anultrasonic stack assembly used in FIGS. 11A-11F having a horn betweendual transducers arranged to inject ultrasonic energy into the horn.Alternately this horn arrangement can be operated with a singletransducer and two boosters or a single transducer and one boosterproviding cantilevered support.

FIG. 13A is a perspective view of an ultrasonic-assisted “cut and seal”assembly having dual ultrasonic transducers applying synchronizedultrasonic energy to a resonant horn that captures a roll havingmultiple layers between the horn and an anvil.

FIG. 13B is a perspective, cut-away view of the ultrasonic-assisted “cutand seal” assembly shown in FIG. 13A to show the blade between the anvilabutting the horn having a corresponding opening or slot to receivetherein the blade when actuated into the horn to cut the part arrangedbetween the horn and the anvil.

FIG. 13C shows two illustrations of FEA analyses of the horn shown inFIGS. 13A and 13B to show an exaggerated direction of flexure ormovement of the horn as the disparate phases of ultrasonic energies areimparted from the dual transducers into the horn from opposite sidesthereof.

FIG. 14A is a perspective view of an ultrasonic-assisted “cut and seal”assembly having dual ultrasonic transducers applying synchronizedultrasonic energy to a resonant horn that captures a roll havingmultiple layers between the horn and an anvil. Alternately this hornarrangement can be operated with a single transducer and two boosters ora single transducer and one booster providing cantilevered support.

FIG. 14B shows two illustrations of FEA analyses of the horn shown inFIG. 14A to show an exaggerated direction of flexure or movement of thehorn as the disparate phases of ultrasonic energies are imparted fromthe dual transducers into the horn from opposite sides thereof.

FIG. 15A is a top or bottom view of a cutting blade sandwiched betweentwo ultrasonic stack assemblies whose transducers output synchronizedultrasonic energy into the cutting blade.

FIG. 15B is a side view of the cutting blade and ultrasonic stackassemblies shown in FIG. 15A.

FIG. 16A is a perspective view of a rotatable resonant cutting bladesandwiched between two ultrasonic stack assemblies whose transducersoutput synchronized ultrasonic energy into the cutting blade, whichoperates like a resonant horn. Alternately this horn arrangement can bedriven by a single transducer.

FIG. 16B is a side view of the cutting blade assembly shown in FIG. 16A.

FIG. 16C is an end view of the cutting blade assembly shown in FIG. 16A.

FIG. 17A is a perspective view of the rotatable cutting blade assemblyshown in FIG. 16A cutting through a thick block of matter, such as food.

FIG. 17B is an end view of the rotatable cutting blade assembly shown inFIG. 17A in which the dual ultrasonic stack assemblies are visible.

FIG. 17C is a side view of the rotatable cutting blade assembly shown inFIG. 17A.

FIG. 18A is a functional illustration of a cutting blade that isconfigured to cut from a top or bottom cutting blade surface throughmatter having a thickness T1.

FIG. 18B a functional illustration of a cutting blade that is configuredto cut through matter having a thickness T2>>T1 and also greater than aheight of the cutting blades.

FIG. 18C is a functional illustration showing how the cutting blade canbe rotated to cut a block of matter at least twice per complete rotationof the cutting blade.

FIG. 19A illustrate a paddle-shaped scrubbing metal welding horn havingelongated slots and scaling protrusions along a scrubbing surface of thehorn.

FIG. 19B illustrates another paddle-shaped scrubbing metal welding hornhaving elongated slots and a single scaling protrusion along each edgeof the horn.

FIG. 19C shows an illustration of an FEA analysis of the horn shown inFIG. 19B.

FIGS. 20A, 20B, and 20C are illustrations of exaggerated FEA analysis ofhorns having different numbers of slots, commensurate with a length(from fixed point to fixed point) of the horn.

FIG. 21 is an illustration of a cross-seal style paddle-shaped horn withkeyhole-shaped slots to facilitate a scrubbing motion along its lateralexposed edge surfaces.

FIG. 22 is an FEA analysis of a prior-art conventional horn in which theback-and-forth movement of the horn is elongated along a height of thehorn, not along a width of the horn.

FIG. 23 is an FEA analysis of a prior-art conventional metal weldinghorn oriented horizontally and dimensioned to have 1 lambda wavelengthalong its width dimension, producing a wavelike undulating movementpattern along its width, which is not suitable for a scrubbing actionalong its full width but rather only at a small portion of its face onthe protrusion shown in yellow.

FIG. 24 is an FEA analysis of a paddle-style horn according to thepresent disclosure showing design principles of placement of the nodesand anti-nodes to produce a scrubbing motion along the horn's width(perpendicular to its height).

FIG. 25 is a perspective view of an ultrasonic welding system accordingto some implementations of the present disclosure.

FIG. 26A is a perspective view of a horn of the ultrasonic weldingsystem of FIG. 25 , according to some implementations of the presentdisclosure.

FIG. 26B is an end view of the horn of FIG. 26A, according to someimplementations of the present disclosure.

FIG. 27 is a top view of a first horn and a second horn of theultrasonic welding system of FIG. 25 , according to some implementationsof the present disclosure.

FIG. 28 is a process flow diagram for a method of ultrasonically weldinga part, according to some implementations of the present disclosure.

FIG. 29 is an FEA analysis of a horn showing design principles ofplacement of the nodes and anti-nodes, according to some implementationsof the present disclosure.

While the present disclosure is susceptible to various modifications andalternative forms, specific implementations and embodiments thereof havebeen shown by way of example in the drawings and will herein bedescribed in detail. It should be understood, however, that it is notintended to limit the present disclosure to the particular formsdisclosed, but on the contrary, the present disclosure is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure as defined by the appended claims.

DETAILED DESCRIPTION

A surprising result discovered by the inventors of the inventionsdisclosed herein is that a very good hermetic seal (against air andliquid) can be formed using dual horns that deliver energy at ultrasonicfrequencies when their frequencies and phases are synchronized. As usedherein, a phase is synchronized when two waveforms are coincident at 0degrees (“push-push”) or 180 degrees (“push-pull”). Any other angles areconsidered asynchronous. Advantageously, only one pass is needed to formthe seal, and the seal can be formed in as little as one second or lesswith a single application of ultrasonic energy (e.g., 0.35 sec). Theseals have produced no leaks and work especially well when the interfaceto be sealed has a complex number of layers to be sealed together. Forexample, so-called Gable tops on milk cartons and the like can have aseal interface involving two layers on one end of the interface, up tofour layers in another section of the interface, and possibly fivelayers at the other end of the interface, depending on how the cartonblank is folded. The sealing problem becomes particularly challengingwhen trying to seal across an interface where different layers arepresent in different sections of the areas along the interface to besealed.

Examples of these complex interfaces to be sealed can be seen in FIGS.2-3 and 6C.

Ultrasonic transducers are devices that convert energy into sound,typically in the nature of ultrasonic vibrations—sound waves that have afrequency above the normal range of human hearing. One of the mostcommon types of ultrasonic transducers in modern use is thepiezoelectric ultrasonic transducer which converts electric signals intomechanical vibrations. Piezoelectric materials are materials,traditionally crystalline structures and ceramics, which produce avoltage in response to the application of a mechanical stress. Sincethis effect also applies in the reverse, a voltage applied across asample piezoelectric material will produce a mechanical stress withinthe sample. Suitably designed structures made from these materials cantherefore be made that bend, expand, or contract when a current isapplied thereto.

Many ultrasonic transducers are tuned structures that containpiezoelectric (“piezo”) ceramic rings. The piezo ceramic rings aretypically made of a material, such as lead zirconium titanate ceramic(more commonly referred to as “PZT”), which have a proportionalrelationship between their applied voltage and mechanical strain (e.g.,thickness) of the rings. The supplied electrical signal is typicallyprovided at a frequency that matches the resonant frequency of theultrasonic transducer. In reaction to this electrical signal, the piezoceramic rings expand and contract to produce large-amplitude vibrationalmotion. For example, a 20 kHz ultrasonic transducer typically produces20 microns of vibrational peak-to-peak (p-p) amplitude. The electricalsignals are often provided as a sine wave by a power supply thatregulates the signal so as to produce consistent amplitude mechanicalvibrations and protect the mechanical structure against excessive strainor abrupt changes in amplitude or frequency.

Typically, the ultrasonic transducer is connected to an optionalultrasonic booster and a sonotrode (also commonly called a “horn” in theultrasonic welding industry), both of which are normally tuned to have aresonant frequency that matches that of the ultrasonic transducer. Theoptional ultrasonic booster, which is structured to permit mounting ofthe ultrasonic transducer assembly (or “stack” as it is commonlycalled), is typically a tuned half-wave component that is configured toincrease or decrease the vibrational amplitude passed between theconverter (transducer) and sonotrode (horn). The amount of increase ordecrease in amplitude is referred to as “gain.” The horn, which isoftentimes a tapering metal bar, is structured to augment theoscillation displacement amplitude provided by the ultrasonic transducerand thereby increase or decrease the ultrasonic vibration and distributeit across a desired work area.

Typically, all of the mechanical components used in an ultrasonictransducer assembly must be structured so that they operate at a singleresonant frequency that is near or at a desired operating frequency. Inaddition, the ultrasonic transducer assembly must often operate with avibrational motion that is parallel to the primary axis (i.e., thecentral longitudinal axis) of the assembly. The power supply for thestack generally operates as part of a closed-loop feedback system thatmonitors and regulates the applied voltage and frequency.

For certain applications, particularly those involving welding ofthermoplastic parts together, ultrasonic welding technology is highlydesirable due to its consistency (particularly when the stack's movementis controlled by a servo-driven motor), speed, weld quality, and otheradvantages. The inventors have discovered that leveraging dual hornssynchronously applying ultrasonic energy to a complex interface having avariety of layers across the area to be sealed surprisingly produces anexcellent airtight and hermetic seal in one pass, by matching the phaseand frequency of the energy delivered through both horns and applyingthe energy on either side of the complex interface. Power to each hornis controlled by an ultrasonic generator that delivers consistent andreliable energy even in noisy environments to the horn. An example ofsuch an ultrasonic generator suitable for use in connection with thesystems and methods described herein is disclosed in U.S. Pat. No.7,475,801, the entirety of which is incorporated herein by reference,and a suitable ultrasonic generator is commercially available fromDukane under the brand name iQ™. Each horn can be driven by an iQ™ultrasonic generator or similar generator capable of outputting aconsistent and reliable ultrasonic energy signal through the horn to apart or parts to be welded or joined. Because the components andconfiguration of an ultrasonic generator would be well known to theskilled person familiar with ultrasonic welding, for the sake ofbrevity, a detailed description of these is omitted because they are notessential for an understanding of the inventions disclosed herein. Eachhorn (or technically the horn's transducer) can be powered by a separatepower supply, or they can be powered by a single power supply with dualpower outputs that can be independently controlled. The entire pass orcycle time from applying the force to the horns 106, 108 to removing theultrasonic energy can be very fast, e.g., 0.35 seconds or even fasterwith a higher amplitude of energy.

The force imparted to a part to be sealed can be adjustable within areasonable range, such as +/−50% from the nominal value for each sizemachine or part. The part's geometry, material, and expectations for thefinished product define choices in operating frequency (e.g., as ageneral rule, lower frequency and higher amplitude for larger parts,higher frequency and lower amplitude for smaller parts). In ultrasonicwelding there are essentially three parameters that need to be adjustedto get a high quality and consistent weld for a specific part: a)amplitude; b) force; and c) weld time (time during which ultrasonicenergy is applied to the part). Most applications call for a short weldtime to maximize yield, particularly in packaging applications wherehundreds or thousands of packages are filled and sealed per hour.Amplitude is often limited by stresses in the horn, so there is apractical limit as to how high the amplitude can be set. This leavesforce, but as force is increased to get a good weld quickly, too muchforce might constrain the movement of the ultrasonic stack and it can bedamaged or destroyed. Or the stack can get stuck akin to jaws closing asa brick wall. If the brick wall does not yield, then the movement of thestack will be difficult to maintain. A Gable top requires more force,whereas a pillow pack requires less force applied by the horns. Thinfilms would require a different ratio of amplitude and force, which canalso be based on the material and speed requirements. The systems andmethods disclosed herein allow for much more flexibility andsignificantly open the process window, meaning that the process becomesmore robust and less sensitive to the usual production variablescompared to conventional approaches.

FIG. 1 is an ultrasonic welding system 100 for sealing together multiplelayers of a part 110. The system 100 includes two ultrasonic weldingstacks (shown in FIGS. 4A and 4B) including a first transducer 102 and asecond transducer 104. The system 100 includes a first horn 106 having afirst welding surface 106 a opposing a second welding surface 108 a of asecond horn 108 defining a gap 112 between the first and second weldingsurfaces 106 a, 108 a. The gap 112 is configured to receive therein thepart 110 having a different number of layers to be sealed along asection of the part 110. The section of the part 110 to be sealed hasbeen shown in exaggerated expanded and slightly unfolded form in FIG. 1for ease of illustration to show the different number of layers presentin this example part 100 from left to right. In reality, these layerswould be pressed against one another when presented in the gap 112.Starting from the left in FIG. 1 , as shown by the dashed lines, thefirst section of the part 110 to be sealed has four layers, followed bya second section having only two layers, followed by a third sectionhaving four layers, and finally ending by a fourth and last sectionhaving five layers. This type of interface is typically found in cartonshaving a Gable top such as shown in FIG. 3A. FIG. 3A shows an examplecarton in a fully assembled configuration, folded in half, andcompletely unfolded into a flat starting configuration. In the latterconfiguration, the complexity of the folds and layers can be seen in thetop of the flattened carton, in which five sections 340 a-f are present.When these are folded to form a Gable top 334, they produce an interfaceas shown in FIG. 1 with multiple layers. The area of the horn 106, 108that contacts the part to be sealed is referred to herein as a “weldingsurface,” meaning that it is a contacting surface of the horn that makescontact with the part to deliver via that surface the ultrasonic energyinto an interface to be sealed of the part to weld (or seal) theinterface. The ultrasonic energy passes through the horn away from thewelding surface and into the part that is contact the welding surface ofthe corresponding horn. Each welding surface 106 a, 108 a of the horns106, 108 makes physical contact with a different area of the part to bewelded (the part's sealing interface), e.g., in the case of a Gable top,on either side of the Gable top to be formed when all the layers aresealed together.

The interface to be sealed can not only have different numbers of layersacross its width but also across its height, as shown in FIG. 3B. Here,as the legend indicates, there are at least five sections 350 a,b,c,d,ethat need to be sealed together to form a hermetic seal. For example,along the elongated width dimension of the interface 110, 310 shown inFIG. 3B, there are four sections having, starting from left to right,four layers 350 b, then two layers 350 c, then four layers 350 d again,terminated by five layers 350 e. However, above these sections along aheight dimension, there is an elongated section 350 a having only twolayers. Thus, taken along the height dimension (which is transverse to alongitudinal direction of the Gable top 310), there is only one sectionin the middle of the interface 310 where two layers are present in thearea to be sealed. Everywhere else, there is a different number oflayers above and below the corresponding sections of the interface 310to be sealed. This type of Gable top 334 is particularly challenging toseal, because of the multi-dimensional changes in the number of layersacross its width, height, and depth (due to the varying thickness of thedifferent layers). Conventional adhesive-free methods are eithertime-consuming and require multiple passes along the interface, orsimply do not produce a hermetic seal that can prevent all liquid fromescaping. The carton 330 can also sometimes include a plastic spout 332protruding from the Gable top to facilitating pouring. The Gable top 334can be opened a la a milk carton for pouring out the liquid contents ofthe carton 334. The present disclosure is particularly well-suited forhermetically sealing Gable tops having many different layers in allthree dimensions.

Another type of part that has a similar type of interface to be sealedis a pillow pack 230, illustrated in FIG. 2 , which has tops or endsthat resemble a Gable top. Pillow packs are usually first joined at afirst seam running lengthwise along the pack, which presents an areathat has multiple layers. The ends 210 of the pillow pack 230 also havemultiple layers as shown by the legend. In this configuration, which issometimes referred to as a 4-2-4-2-4, there are four layers in a firstsection of the end 230, followed by two layers, then four layers again,followed by two layers, and finally four layers. The different number ofthe layers are thus arranged across a longitudinal direction of theGable top 210 of the pillow pack 230. Again, this type of part with adifferent number of layers presents a particular challenge to seal. Thesynchronized dual horn/stack configuration of the present disclosure canseal pillow packs so that they are airtight without any leaks. Thepillow pack shown in FIG. 2 and the carton 330 shown in FIG. 3A can becomposed of a polymeric film or a thermoplastic material.

Another type of part having interfaces that can be sealed using theinventions disclosed herein is a fluid-filled pouch having a valve or apierceable sealing element that can be pierced, e.g., by a straw, suchas described in U.S. Patent Application Publication No. 20040161171A1.An example system configured to seal using the ultrasonic technologydisclosed herein a fluid-filled type of pouch is shown and described inconnection with FIGS. 5A-5D. A popular type of pouch is sold in the U.S.under the brand CAPRISUN®. An example system configured to seal usingthe ultrasonic technology disclosed herein a part having a spout isshown and described in connection with FIGS. 6A-6C.

In liquid-filled pouches when a liquid is already present in the pouchbefore the pouch is sealed, the synchronized ultrasonic energy from thedual horns produces a vibration at the interface that pushes awayliquids from the interface area, further contributing to creating ahermetic seal. In other words, a surprising benefit of the applicationof dual synchronized ultrasonic energy to a part filled with liquid isthat the vibrations produced by the application of the energy from bothsides of a to-be-sealed interface tends to vibrate away any droplets ofliquid present around the interface, thereby allowing the layers of theinterface to be sealed together without getting liquid trappedtherebetween and creating opportunities for leaks. Microscopic leaksalso present a health and spoliation hazard, allowing bacteria or otherpathogens into the sealed pouch or mold to form around the seal. Bycreating a hermetic seal in one pass of the dual horns, wherein thevibrations produced by the application of ultrasonic energy from bothsides of an opening of a liquid-filled pouch shake off liquid at theinterface before being sealed, an additional advantage can be seen fromthe synchronized dual horn configuration disclosed herein.

Returning to FIG. 1 , the system includes an actuator assembly 116operatively coupled to the ultrasonic welding stack (FIGS. 4A and 4B)and configured to cause the first welding surface 106 a of the firsthorn 106 to move relative to the second welding surface 108 a of secondhorn 108. The movement of the horns 106, 108 together can be aided bycorresponding frames 130, 132 to which the respective horns 106, 108 arecoupled, which frames 130, 132 form part of the actuator assembly thatmoves the horns 106, 108 together and apart from one another. Onemovement of the horns 106, 108 together to clamp a part to be sealed andthen apart following application of the ultrasonic energy to the part isreferred to as a single pass or cycle. The actuator assembly 116 caninclude one or more motors, such as a servo motor. The two weldingsurfaces 106 a, 108 a are directly opposed one another and form mutuallyparallel planes that are orthogonal to an orientation of the horns 106,108. The two horns 106, 108 can be seen as moving toward one anotherlike a jaw that opens and closes such that the exposed end weldingsurfaces 106 a, 108 a thereof contact corresponding opposite surfaces ofa part or part interface to be sealed. The corresponding ultrasonicenergy from the transducers 102, 104 imparted to the horns 106, 108,which is synchronized in frequency and phase, is outputted along thesame dimension in opposite directions. Each of the dual ultrasonicwelding stacks can include an optional booster 140, 142, shown in FIG.4A, which amplifies the energy emitted from the transducers 102, 104before passing into the horn 106, 108. Again, the presence of theboosters 140, 142 is optional, and the configurations shown in FIGS. 5Aand 6A lack a booster. In these configurations, the transducer 102, 104is mounted directly to the horns 506, 508 (FIG. 5A) and 606, 608 (FIG.6A).

A controller 120, which can be one or more controllers, is operativecoupled to the ultrasonic welding stacks and to the actuator assembly116. The controller 120 is configured to cause the actuator assembly 116to urge the first and second welding surfaces 106 a, 108 a of the horns106, 108 toward one another until contacting the part 110. Apredetermined force can be applied to the horns 106, 108 to essentiallyclamp the part 110 between the welding surfaces 106 a, 108 b and keepthe folded layers together. For example, the maximum force imparted bythe horns on the part 110 can be set at 4500N, but will depend on theapplication including the thickness of the interface and the materialsto be joined together. The controller 120 applies toward the part 110 afirst ultrasonic energy via the output of the first horn 106 and asecond ultrasonic energy via the output of the second horn 108 such thata frequency and a phase of the first and second ultrasonic energies aresynchronized as the first and second ultrasonic energies are applied onboth sides of the part 110 simultaneously, to thereby the seal thelayers together, such as the layers 350 a,b,c,d,e shown in FIG. 3B. Asmentioned above, an example ultrasonic generator suitable to generateultrasonic energy through a transducer into a horn is described in U.S.Pat. No. 7,475,801 and is commercially available from Dukane under anyof the iQ™ line of ultrasonic generators.

Synchronization of two ultrasonic generators can be accomplished byproviding a communication connection between the two generators so thattheir respective outputs to the transducers 102, 104 are synchronized infrequency and phase. Alternately, a generator such as the one describedin the patent above can be modified to provide two outputs that aresynchronized in frequency and phase and provided to a respectivetransducer 102, 104. The generators (whether separate or integrated withdual outputs) can be arranged in a master-slave relationship wherein oneof the generators is assigned to be a master. The phase of the mastergenerator is auto-locked to its ultrasonic stack's feedback using aPhase Lock Loop (PLL), and the master generator instructs the slave viathe communication connection to mimic the same phase at the zerocrossings (at 0 or 180 degrees) and ignore the slave's own phase andfrequency feedback. This allows the slave's phase to drift in the samemanner as the master. Phase drifts can occur, e.g., due to thermaleffects, so by locking the phase of the slave to the master allows thephase (and therefore by implication the frequency corresponding to thezero crossings of the ultrasonic energy signal's phase) to besynchronized in both transducers 102, 104.

FIG. 7 illustrates example waveforms, which are not to scale, ofsynchronized ultrasonic energy applied to the first transducer 102 andto the second transducer 104. Here, synchronized refers to the energyhaving the same frequency, f1, and phase. The amplitude, A, may or maynot be identical for both horns. Depending on the application and thethickness of the part closest to the horn 106, 108, a differentamplitude can be applied through the first horn 106 relative to thesecond horn 108. Just as the frequency, f1, is matched in both horns106, 108, so too the phase of both energies is time synchronized so thatthe zero-crossings and the peaks of the energy over time coincide at thesame time as shown by the dashed lines in FIG. 7 . The frequency, f1, ofthe energy generated in one horn 106 (or transducer 102) can be within 3Hz of the energy generated in the other horn 108 (or transducer 104).Using two, synchronized horns halves the energy attenuation throughmultiple layers, such as when sealing a Gable top compared to a singlehorn setup. For example, in a single-stack configuration, the ultrasonicenergy must pass through 4-5 layers of a Gable top, producing up toabout a 50% attenuation or loss of ultrasonic energy/amplitude. Bycontrast, when using the synchronized dual horns according to thepresent disclosure, the energy from one horn only passes through 2 or2.5 layers (the energy from the other side similarly passes through onlyhalf the number of layers compared to a single-stack configuration), andhence the energy/amplitude losses are only about 20-25%, producing ahigh quality weld or seal without burning the layers or creating anyvisual artifacts on the outer surface of the interface being sealed.

It has been found that the frequency of the ultrasonic energy deliveredthrough both of the transducers 102, 104 to the horns 106, 108 isbetween about 15-70 kHz (e.g., ±10%). Particularly effective results areseen with 15 kHz, 20 kHz and 30 kHz. The frequency and phase of theultrasonic energy delivered through both transducers 102, 104 to thehorns 106, 108 to seal the part are synchronized in time so that peakamplitude of the ultrasonic energy is delivered simultaneously on bothsides of the part to be sealed. The amplitude of the ultrasonic energycan be controlled independently on both transducers 102, 104. Afrequency of 20-35 kHz is particularly suited for sealing smaller orthinner packaging, and higher frequencies can be used for sealing largeror thicker packaging.

An example “scrubbing” configuration is shown in FIGS. 5A-5D. In thisconfiguration, there are two transducers 102, 104 synchronized infrequency and phase just as in the previous configurations, but thehorns 506, 508 are positioned so that their sides come into contact topress against a to-be-sealed interface of a part, such as a thin filmhaving a thickness in a range of 10-20 um or even over 100 um, or athin, non-woven film where the thickness can vary along the length ofthe interface. The variation in thickness can be ±2 um at unpredictablelocations along the length of the interface. Thus, while the applicationof energy may be uniform, the thickness of the interface (e.g., whichcan be composed of just two layers being sealed together) can vary alongthe length of the interface being sealed together, creatingopportunities for small leaks or uneven welding of the seal. Theso-called scrubbing action leverages the tiny, mechanical Y-axis motionsproduced by the two horns 506, 508 vibrating relative to one another asthe frequency- and phase-synchronized ultrasonic energy is impartedthrough the transducers 102, 104 to the horns 506, 508. These vibrationsproduce very short, rapid back and forth motions in the horns 506, 508that resemble a scrubbing movement, which has been found to produce veryhigh quality hermetic seals where the interface has a non-uniformthickness, such as when the interface is a thin film or non-woven film.The configuration shown in FIGS. 5A-5D also allow for gentler control ofamplitude and force as applied to a thin interface, and a wider processwindow.

In FIG. 5A, two ultrasonic stacks, each including a transducer 102, 104and a horn 506, 508. The horns 506, 508 are positioned adjacent oneanother so that their respective side welding surfaces 506 a, 508 a movetoward one another. These welding surfaces 506 a, 508 a are parallel tothe Y-Z plane and extend along a length along the Z axis. The ultrasonicenergy is applied through the transducer 102 along the Y axis direction,and the ultrasonic energy through the second transducer 104 is appliedin the opposite direction along the Y axis direction. The side surfaces506 a, 508 a vibrate past one another as the part is positionedtherebetween and the frequency- and phase-synchronized ultrasonic energyis applied through the horns 506, 508 simultaneously. Thin film or thinnon-woven materials form a hermetic seal with only one pass ofultrasonic energy through the horns 506, 508. Only two horns 506, 508and a single pass are required to produce a consistent, hermetic seal,free from burns or visual artifacts or microscopic leaks. While a thinfilm or non-woven material has been described in these examples, thescrubbing aspects disclosed herein also work with welding metal films,metal foils or thin metals, or any combination of thin film, non-wovenmaterial, or metals. For example, scrubbing is particularly effective atsealing metals together, but also is effective at sealing dissimilarmaterials together, e.g., a non-woven material to a metal film or foil.

In FIG. 5B, a close-up of the two side welding surfaces 506 a, 508 a canbe seen of the horns 506, 508. The welding surface 506 a extends away toform a smaller exposed surface area compared to the flat side weldingsurface 508 a. In this way, the side welding surface 506 a acts as a“scrubber” as it moves rapidly back and forth along the Y-axis directionunder ultrasonic influence when a part 110 is positioned between the twohorns 506, 508. An example configuration can be seen in FIG. 5C, wherethe horns 506, 508 are in contact with one another. The part 110, whichfor example can be a pouch having an open end that needs to be sealed,has its open end positioned between the horns 506, 508, which would“scrub” the two layers of the interface together as the ultrasonicenergy is applied from opposite sides of the interface. The mechanicalaction coupled with the heat produced by the ultrasonic energiescooperate to produce a hermetic seal free from artifacts or microscopicleaks. FIG. 5D shows the horns 506, 508 spaced apart. The part'sinterface 110 is positioned in the gap between the two side weldingsurfaces 506 a, 508 a, which are urged toward one another along theX-axis direction until their side welding surfaces 506 a, 508 a contactwith opposite sides of the interface 110. A force is applied to thehorns 506, 508 while the ultrasonic energy is applied through thetransducers 102, 104 and into the horns 506, 508, producing the tinymechanical vibrations referred to as the scrubbing action along themelting of the interface 110 where the welding surfaces 506 a, 508 apress against it. Once the horns 506, 508 are retracted, a hermetic sealis present at the part's interface 110, requiring only one pass ormovement of the horns 506, 508 and one application of the synchronizedultrasonic energies.

Another synchronized dual-horn configuration is shown in FIGS. 6A-6C,which is suitable for sealing parts having complex geometries, such as aplastic or metal spout for a liquid pouch, pillow, or container. Here,two transducers 102, 104 are positioned relative to a first contouredhorn 606 and a second contoured horn 608 having an opening 612 (bestseen in FIG. 6C) to receive therein a part 332 to be sealed. The end ofthe horns 606, 608 have a knurled surface 608 b (best seen in FIG. 6B),to clamp around the part 332 (which can be a round spout, for example),which transition to a ribbed welding surface 608 a that receives theround (or oval) part 332. The other horn 608 has the same weldingsurfaces, so that they press against one another, the part 332 is heldin place and a uniform application of energy is evenly distributedaround the part to produce a consistent weld. The contoured horns 606,608 can be shaped to match the contour of any part's geometry, includinground, oval, or any irregular geometry.

A further dual-horn configuration is schematically illustrated in FIGS.8A and 8B. Two horns 806, 808 are of the rotary type, and those familiarwith the art of ultrasonic welding will appreciate rotary horns and howthey are driven, the details of which are not pertinent to anunderstanding of this configuration. An example of a configurationincluding a rotary horn and a stationary anvil is shown in U.S. Pat. No.10,479,025, granted Nov. 19, 2019, and entitled “Apparatus forfabricating an elastic nonwoven material,” the entirety of which isincorporated herein by reference. According to the concepts disclosedherein, two rotary horns 806, 808 are proposed as shown in FIG. 8A, inwhich both horns 806, 808 contact both sides of a part 810 havingmultiple layers 840 a, 840 b (though more than two are contemplated),such as a non-woven material having multiple layers to be joined orsealed together, which passes between the two horns 806, 808 as thehorns are rotating at the same angular speed, w 1. The frequency andphase of the respective ultrasonic energies being imparted to the horns806, 808 are synchronized, as disclosed herein, producing a high qualityseal or joining of the layers 840 a, 840 b of the part 810 in one passthrough the horns 806, 808. A force can be applied to the layers 840 a,840 b of the part 810 between the horns 806, 808, as the part 810 passestherebetween. For ease of illustration, the physical separation betweenthe layers 840 a, 840 b has been exaggerated in FIGS. 8A and 8B to showhow they are joined together by the dual rotary horns 806, 808, whichare driven by respective transducers 102, 104. Each of the transducers102, 104 is powered by corresponding outputs of one or more ultrasonicgenerators as described above that produce ultrasonic energy outputs toboth transducers 102, 104 that is synchronized in both frequency andphase. Thus, in this configuration, and angular speed w1 of the hornsand frequency and phase of the ultrasonic energy applied to each hornare synchronously matched.

The layers 840 a, 840 b of the part 810 are drawn between the two horns806, 808, which are rotating at the same angular speed as ultrasonicenergy having the same frequency and phase is imparted to both horns806, 808 simultaneously. By applying ultrasonic energy matched infrequency and phase to both horns 806, 808 simultaneously allows theamplitude of the energy to be reduced compared to a configuration havingonly one energized stack, which produces higher throughput (e.g.,exceeding 2000 feet per minute) while expanding the process window.

An ultrasonic welding method for sealing together multiple layers(forming a to-be-sealed interface) of a part is also disclosed. Themethod includes moving a first welding surface of a first horn toward anopposing a second welding surface of a second horn to close a gapbetween the first welding surface and the second welding surface untilthe first and second welding surfaces contact a part, such as a parthaving a different number of layers along a section of the part to besealed. Responsive to contacting the part, the method applies toward thesection of the part between the two horns a first ultrasonic energy viaan output of a first horn and a second ultrasonic energy via an outputof a second horn such that a frequency and a phase of the first andsecond ultrasonic energies are synchronized as the first and secondultrasonic energies are applied on both sides of the partsimultaneously, to thereby seal the layers together. The respectiveoutput tips of the first and second horns are arranged to point towardone another. Importantly, the closing and retraction of the horns occursonly one time to seal the interface without causing any burns, visualartifacts, or leaving any air or liquid leaks along the interface. Bycontrast, conventional approaches require multiple horn movements (e.g.,three or more) to create a seal, which is time consuming and increasesthe risk of burning parts of the interface or creating undesirablevisual artifacts particularly in thinner areas of the interface (e.g.,when sealing a gable top).

Aspects of the present disclosure are also applicable to so-calledfar-field welding where the area to be welded is located a physicaldistance away from the horn output or surface from which the ultrasonicenergy transitions from a solid substrate into the area outside thehorn. In many applications, the location of the joint in regard to thearea of horn contact can be critical, because the ultrasonic energy musttravel through the material to reach the desired area of melt.Near-field and far-field welding refer to the distance that ultrasonicenergy is transmitted from the point of horn contact to the jointinterface. For example, when the distance between the horn output orsurface and the joint interface to be welded is ¼″ (6 mm) or less, itcan be considered near field. By contrast, when the distance is greaterthan ¼″ (6 mm), the weld can be considered far field. Whenever possible,it is always best to weld near field. This is because far-field weldingrequires higher than normal amplitudes, longer weld times, and higherforces to achieve a comparable near-field weld. Generally speaking,far-field welding is advised only for amorphous resins, which transmitenergy better than semi-crystalline resins. However, with the two-hornconfiguration disclosed herein, the applications for far-field weldingcan be expanded because the energy is being applied from two sides of aninterface simultaneously.

The dual horn aspects disclosed herein are also applicable toultrasonic-assisted metal wire drawing processes or ultrasonic-assistedmetal forming processes. Conventional metal drawing or forming processescontemplate using one source of ultrasonic energy applied to a hardsteel die or the like as the wire or metal is pulled through the die.The pulling force is very high and eventually the die dulls and requiresreplacement. The present disclosure contemplates applying ultrasonicenergy synchronized in frequency and phase to two sides of the diesimultaneously as the wire or metal is drawn through the die by anexternal pulling force. The energy produces vibrations in the die,causing the die to act as a lubricant, thereby reducing the forcesrequired to draw the wire through the die. The die will requirereplacement at a longer time interval, improving throughput forprocesses involving metal wire drawing or metal forming.

Examples of ultrasonic-assisted metal forming processes usingsynchronized ultrasonic energy as shown in FIGS. 9A-9E. For convenience,“ultrasonic welding system” as used herein encompassesultrasonic-assisted metal forming processes such as shown in FIGS.9A-9E. While these processes do not weld parts together in thetraditional or conventional sense, they operate using the synchronizedfrequency principles disclosed herein and are subsumed under theumbrella of ultrasonic welding systems. FIG. 9A illustrates an exampleconfiguration of a wire drawing system 900 having a die 902 withmultiple ultrasonic stacks (including transducers and horns) 904 a, 904b, 904 c, 904 d applying ultrasonic energy that is synchronized infrequency and phase to various parts of the die 902. The die 902operates as a horn in this example, oscillating mechanically back andforth in a vibration movement according to the ultrasonic energiesimparted into it by the transducers 904 a, 904 b, 904 c, 904 d. Wiredrawing and metal-forming systems are well known in the art, and theirconfiguration is also well known to those familiar with these arts, andare not reproduced here for ease of discussion. The basic configurationincludes some sort of die 902, which in the example shown in FIG. 9A isshaped such that when a wire having an initial gauge or thickness isdrawn through a gap 915 in the die, typically by pulling, the gap 915 ofthe die 902 has a starting diameter that is larger than a terminatingdiameter so that the diameter of the wire 910 as it is pulled throughthe die 902 decreases to a desired gauge or thickness (912). The wire910 is pressed against a first part-interfacing surface 915 and a secondpart-interfacing surface 917 of the die 902 as it is drawn through thegap 915 of the die 902. The inventive concept here is to use pairs ofsynchronized (in frequency and also in phase) ultrasonic stacks thatapply energy to the die 902 (which in this ultrasonic embodiment becomesa non-resonant part) in a manner that causes the parts of the die 902 tomechanically vibrate, producing a number of benefits over conventionalwire-drawing techniques that do not use frequency-synchronizedultrasonic energy. An example for applying ultrasonic vibrations to anon-resonant part is disclosed in U.S. Pat. No. 9,993,843, titled“Adapter for Ultrasonic Transducer Assembly,” the entirety of which isincorporated herein by reference.

In the assembly 900 shown in FIG. 9A, there are four ultrasonic stacksincluding transducers 904 a, 904 b, 904 c, 904 d arranged about the die902 to apply energy into the die 902 at the transducer locations. In apractical application, these stacks can be deployed in pairs (e.g., 904a with 904 d, or 904 b with 904 c). In other words, even though fourultrasonic stacks are shown in FIG. 9A, it is contemplated that a singlepair of stacks, e.g., 904 a and 904 d, can be employed instead. Again,the energy is fully synchronized in frequency and phase in oneembodiment as shown by the example waveforms in the figures. In otherembodiments, it can be advantageous to have the frequency onlysynchronized but with two more different phases among the fourultrasonic stacks 904 a, 904 b, 904 c, 904 d. While the representativewaveforms shown in the figures are shown as having the same frequencyand phase relative to one another, it is understood that the phasesamong any of the transducers can be different or asynchronous. Thesynchronized energy applied through the die (operating as a non-resonantpart) 902 via the transducers 904 a, 904 b, 904 c, 904 d causes the die902 to mechanically vibrate rapidly (at or around the frequency of theultrasonic energy), acting as a sort of lubricant to the wire as it isdrawn through the gap 915 of the die 902. Less pulling force is alsorequired compared to conventional techniques because the “lubricated”die 902 that is vibrating rapidly allows the wire 910 to be pulledthrough the die more quickly and with less force and without the use ofliquid or wet lubricants. This kind of wire drawing is called dry wiredrawing because no lubricants or liquids are used at the wire-dieinterface to facilitate the wire drawing process. The wires 910 drawn bythis process advantageously have a superior smooth surface finish withfew to no blemishes, and result in faster draw speeds, lower draw force,and reduce or avoid the need to use any external lubricants at thewire-die interface. The wire 910 can be composed of copper, aluminum, orany other electrically conductive metal or metal alloy, and can be solidor stranded.

Returning to FIG. 9A, the direction of the wire drawing is from left toright while viewing the figure, with the thicker portion of the wire 910being drawn through an input section of the gap 915 of the die 902 toproduce the thinner portion of the wire 912 on the right side at anoutput section of the die 902. Four ultrasonic stacks 904 a, 904 b, 904c, 904 d are positioned about the die 902, which acts as a mechanicallyvibrating horn when ultrasonic energies are applied by these transducersthrough the die 902. The top die 904 a is positioned to abut a topsurface of the die 902, and a bottom die 904 d is positioned abut abottom surface of the die 902. The top and bottom die 904 a, 904 d arearranged to direct their respective ultrasonic energies toward oneanother and toward the wire 910 being drawn through the die 902. Theseenergies are synchronized in frequency, and can optionally also besynchronized in phase. In addition, two other transducers 904 b, 904 care arranged on end surfaces of the die 902 above and below the outputsection of the die 902. These transducers 904 b, 904 c direct theirrespective ultrasonic energies parallel to one another and in adirection opposite to the direction of travel of the wire 910 throughthe die 902. This produces a landscape of harmonized ultrasonic energieswithin the die 902 all vibrating at the same frequency, which causes thesurface interfaces between the die 902 and the wire 910 to mechanicallyvibrate rapidly and uniformly in multiple directions. Without thesynchronized frequencies, the vibrations within the die will not beuniform, which would cause the wire to have undesirable surfaceartifacts as it is drawn through the die and/or to experience differentmechanical stresses or strains or uneven deformations along its diameteras it is pulled through the die, causing one side of the wire to bedrawn at a different rate compared to another side of the wire.

Another ultrasonic-assisted metal forming process 920 is shown in FIG.9B in which a metal part 930 is undergoing a deep drawing process aidedby a die 922 and a punch 926. Three ultrasonic transducers 924 a, 924 b,924 c are arranged on the die 922 and the punch 926 to facilitate a deepdrawing operation on the part 930. In this example, an ultrasonic stack924 c is arranged to abut the punch 926 and to direct its ultrasonicenergy in the same direction as the punch moves to complete the deepdrawing process on the part 930. Two other ultrasonic stacks 924 a, 924b are arranged to abut opposite surfaces of the die 922 so that theirrespective energies are directed toward one another and to the part 930being punched through the punch-die interface. The ultrasonic frequencyof the transducers 924 a, 924 b, 924 c is synchronized, and optionallythe phase can also be synchronized. Alternately, the phase of theultrasonic energy applied through the punch 926 by the transducer 924 ccan be out of phase relative to the synchronized phase of the energyapplied by the transducers 924 a, 924 b to opposite sides of the die922. The part 930 is received in a gap 925 of the die 922, which likethe die 902 shown in FIG. 9A operates as a non-resonant part to thestacks 924 a, 924 b. The die 922 has a first part-interfacing surface935 and a second part-interfacing surface 937 that contact the part 930as it is undergoing the deep drawing process. The synchronizedvibrations of the die 922 cause the part to vibrate back and forthrelative to the die at the first and second part-interfacing surfaces935, 937 (and other part-interfacing surfaces in contact with the die),primarily those surfaces involved in being deformed or bent during thedeep drawing process.

An extrusion-type ultrasonic-assisted metal forming process 940 is shownin FIG. 9C in which a metal part 950 undergoes extrusion through a die942 by a ram 946 applying a pushing force against the metal part 950 asit is extruded through a gap 945 in the die 942. Similar to the assemblyshown in FIG. 9A, four ultrasonic stacks 944 a, 944 b, 944 c, 944 d arearranged about the output section of the die 942 and their ultrasonicenergy outputs are synchronized in frequency and optionally in phase.The physical arrangement of the ultrasonic stacks 944 a, 944 b, 944 c,944 d in this assembly 940 is similar to the arrangement of the stacks904 a, 904 b, 904 c, 904 d shown in FIG. 9A. The arrows indicate thedirections of the respective ultrasonic energy outputs from thetransducers of the stacks 944 a, 944 b, 944 c, 944 d, and these areprovided through the die 942 as the part 950 is extruded by the impactforce of the ram 946 through the die 942. There are at least fourpart-interfacing surfaces 955 a, 955 b, 957 a, 957 b of the die 942 incontact with the corresponding surfaces of the part 950 as it undergoesthe metal forming process.

A forging-type ultrasonic-assisted metal forming process 960 is shown inFIG. 9D in which a metal part 970 undergoes a compression force by a die962. Four ultrasonic stacks including transducers 964 a, 964 b, 964 c,964 d are arranged to abut sections of the die 962, and their ultrasonicenergies are synchronized in frequency and optionally also in phase. Atop transducer 964 a is arranged to abut a top surface of a top sectionof the die 962 and direct its energy downwards toward the part 970. Abottom transducer 964 c is arranged to abut a bottom surface of a bottomsection of the die 962 and direct its energy upwards toward the part 970and towards the top transducer 964 a. As shown in FIG. 9D, a first sidetransducer 964 d is arranged to abut a left side of a bottom section ofthe die 962 and direct its energy into the die 962 from left to right asviewed in the figure. A second side transducer 964 b is arranged to abuta right side of a top section of the die 962 and direct its energy intothe die 962 from right to left and in a direction opposite to that ofthe first side transducer 964 d. The part 970 is provided in a gap 965and contacts at least a first part-interfacing surface 975 of the die962 and a second part-interfacing surface 977 of the die 962, whichagain operates like an ultrasonic non-resonant part/horn when theultrasonic energies are applied to the horn or die 962. Thisconfiguration creates a consistent and uniform vibration profile at thedie-part interfaces to allow uniform compression at a faster speedcompared to conventional metal forging processes.

A rolling-type ultrasonic-assisted metal forming process 980 is shown inFIG. 9E in which a part 990 undergoes a rolling force by two rolls 982a, 982 b. The part 990 is drawn through a gap 985 between the rolls 982a, 982 b in a direction of arrow A so that its cross sectional area isreduced. The part 992 contacts a first part-interfacing surface 995 ofthe top roll 982 a and a second part-interfacing surface 997 of thebottom roll 982 b. A first ultrasonic stack 984 a is configured to abuta top roll 982 a, and a second ultrasonic stack 984 b is configured toabut a bottom roll 982 b. The ultrasonic stacks 984 a, 984 b arepositioned to output their respective ultrasonic energy in a direction Bthat is transverse or perpendicular to the direction of arrow A. Thisprocess 980 produces a much smoother rolling operation without the useof external lubricants and without creating artifacts on the surfaces ofthe part 990 being drawn through the rolls 982 a, 982 b.

FIG. 10 illustrates two example configurations of two packaging systemsin which any of the ultrasonic welding systems disclosed herein can beincorporated. Those skilled in the art of packaging will readilyappreciate that the machines can be oriented so that the packages orpouches or bags or other receptacles filled with matter (food, liquids,powders, etc.) are formed along a horizontal orientation or a verticalorientation. Horizontally arranged packaging systems are calledhorizontal form, fill and seal (HFFS) packaging systems, and verticallyarranged packaging systems are called vertical form, fill and seal(VFFS) packaging systems. The implementations and embodiments disclosedherein can be oriented horizontally or vertically, and apply equally toboth HFFS and VFFS packaging systems. In the left diagram of FIG. 10 ,an example VFFS packaging system 1000 a is shown. And in the rightdiagram, an example HFFS packaging system 1000 b is shown. To reiterate,this shows one example configuration of many, and those familiar withthe packaging arts will appreciate that other configurations will varyfrom those shown in FIG. 10 . These exemplars are for ease of discussionto explain where the ultrasonic welding systems herein can be introducedinto the packaging system process to seal and optionally cut the partsinto singulated parts filled with matter.

The example VFFS packaging system 1000 a includes a roll of film 1002that is conveyed through a system of rollers in a vertical directiontoward a forming tube 1006 into which product 1004 or any other matterto fill the pouch or pocket or bag or container formed by the filmbefore entering a sealing unit 1012, which optionally can cut the filmto singulate the part and thereby separate it from the roll of film1002. Any of the ultrasonic welding systems disclosed herein, inparticular but not limited to those discussed in the subsequent figures,can be incorporated as the sealing unit 1012 shown in the VFFS packagingsystem shown in FIG. 10 .

The example HFFS packaging system 1000 b includes a roll of film 1020that passes through a series of rollers 1022 toward a forming box 1030where the film is folded to make a pouch or other vessel to contain aproduct or matter 1026 conveyed by a belt conveyor 1024 toward theforming box 1030. The product or matter 1026 enters the forming box 1030to be loosely contained therein until its top can be sealed in a finseal roller 1034. The to-be-formed pouch 1048 or package enters an endsealer and cutter assembly 1040, where the sides of the pouch are sealedand cut to singulate the package or pouch 1050 before it is presented toa discharge conveyor 1042. To singulate a to-be-formed package 1048 ontwo open sides, the sealer and cutter assembly 1040 needs to make twopasses as the to-be-formed package 1048 passes through the assembly1040. The assembly 1040 can rotate, for example, and this is the sectionwhere any of the ultrasonic welding systems disclosed herein can besubstituted. The ultrasonic welding systems herein overcome manydisadvantages presented in conventional sealer and cutter assemblies,including only one pass needs to be made, a higher quality hermetic sealresults, and the throughput of package 1050 singulation is increased.Additional benefits compared to traditional heat sealing technologiesinclude reduced machine down time; no heat-up or cool-down required—theultrasonic energy is immediately available for welding; weld parameterscan be changed on-the-fly with immediate response; the ultrasonicwelding is gentle to the product and packaging material and does notproduce visual or other undesirable artifacts at the sealing interface;no burning of packages or material at the machine stop situs; no filmshrinkage; and no thermal impact to the product being packed inside thepouch or container. Thermal seals tend to be, on average, 13 mm (½″)wide at the top of a package; however, ultrasonic sealing according tothe present disclosure can produce seals as narrow as 1-2 mm wide. Thebag or container can be made smaller, as well, because the narrow,quality seal allows for smaller headspace requirements, withoutexcessive oxygen transmission or the product (bag) getting caught in awider seal. Accordingly, material savings of up to 25% can be achievedwith smaller bag sizes and an overall small seal real estate.

FIG. 11A illustrates a perspective view of an ultrasonic-assisted “cutand seal” assembly 1100 having dual ultrasonic transducers applyingsynchronized ultrasonic energy to a horn 1110 (shown in FIG. 12 ) thatcaptures a roll 1102 having multiple layers between the horn 1110 and ananvil 1114 a, 1114 b. Alternately, the horn 1110 can be driven by asingle ultrasonic transducer in applications requiring a lower power toweld but still benefiting from the horns scrubbing action. Thisconfiguration leverages the “scrubbing” action described herein, and isparticularly effective at sealing two or more films in a roll 1102together. References will be made to FIGS. 11A, 11B, 11C, 11D, 11E, 11F,and 12 , which show how the horn 1110, transducers 1112 a, 1112 b, andanvil 1114 a, 1114 b cooperate to cause the ultrasonic energy to apply ascrubbing action to the roll 1102 while sealing the roll in a sectionbetween two adjacent sections 1104 of the roll 1102 in two placessimultaneously while also optionally carrying a cutting operation to cutan area between the two sealed sections. Again, while these exampleconfigurations are shown in a horizontal orientation suitable for anHFFS packaging system, these examples apply equally to a VFFS packagingsystem and can be oriented vertically. Those familiar with filmpackaging systems will readily appreciate that the orientation does notmatter for implementing the novel and inventive concepts herein.

In this example, a multitude of pouches or pockets 1104 d, 1104 e, 1104f are made from the roll 1102, which are formed between two layers 1104a, 1104 b of a film or other material, and which need to be sealed, suchas after they have been filled with content matter (e.g., liquid, afood, powder, or the like). So-called pillow pouches or bags are wellknown in the packaging industry, and traditionally, they are formedalong a continuous roll, and then conventionally sealed using heat andthen later cut to singulate the pouches from the roll into individualitems. Only those structures and devices that are pertinent to carryingout the claimed invention are described here, because it is assumed thatthe person skilled in the packaging arts, and in particular pillow pouchpackaging will be very familiar with machines that are employed to fill,seal, and cut the roll into individual pouches.

The present disclosure advances the art of pillow pouch packaging byintroducing at least two ultrasonic transducers 1112 a, 1112 b thatapply ultrasonic energy that is synchronized in frequency and phase intoa horn 1110. An example of this configuration can be seen in FIG. 11A.The transducers 1112 a, 1112 b are arranged relative to the horn 1110 sothat they direct their respective ultrasonic energies toward one anotherinto the horn in a direction that is transverse to a direction of travelof the roll 1102 (e.g., from left to right indicated by the arrow X). Asthe roll 1102 travels in the direction X between the anvils 1114 a, 1114b and the horn 1110, either the anvils 1114 a, 1114 b or the horn 1110or both are brought toward one another to clamp a section 1102 a of theroll therebetween. FIG. 11C shows a section 1102 a of the roll almostready to be clamped between the horn 1110 and anvils 1114 a, 1114 b. InFIG. 11D, the section 1102 a of the roll can be seen clamped in aU-formation between the horn 1110 and the anvils 1114 a, 1114 b. Theanvils 1114 a, 1114 b are clamped together by moving them in thedirection of arrows A and B as shown in FIG. 11D while the horn 1110 israpidly vibrated up and down in the bidirectional direction indicated byarrow C. This rapid up and down mechanical movement of the horn (see FEAanalysis in FIG. 12 ) caused by the synchronized ultrasonic energiesapplied by the transducers 1112 a, 1112 b cause a first horn interface11120 a and a second horn interface 1120 b (best seen in FIG. 11E) toundergo a “scrubbing” action against the portion of the roll 1110trapped between the interfaces 1120 a, 1120 b and respective anvils 1114a, 1114 b to create two seals simultaneously in a single pass (e.g., theback of the forward pouch 1104 d and the front of the next pouch 1102 con the roll 1102. The advancing roll 1102 needs to pause only for aslong as the ultrasonic energies can be applied, and then can resume toseal the next advancing pouch 1104 c. This rapid movement creates auniform seal among the layers of the roll 1102 in two placessimultaneously along the section 1102 a of the roll 1102. A gap ortrough 1130 b formed in an end 1122 of the horn 1110 as shown in FIG.11E can receive an optional blade 1116 having a sharp tip 1124, whichcan cut the section 1140 of the roll 1102 at the same time as the twoseals are being formed at the horn interfaces or part-interfacingsurfaces 1120 a, 1120 b, which is best seen in FIG. 11F. This dualaction is referred to as a “cut and seal,” because these two operationsare performed simultaneously, increasing the throughput of the roll andsingulation or individuation of the pouches or bags. The section betweenthe two seals is referred to as an intra-seal gap 1102 a. The anvil 1114a has a surface 1123 that presses against the part 1104 of the roll 1102adjacent to the first part-interfacing surface 1120 a of the horn 1110.The anvil 1114 b also has a surface 1125 that presses against the part1104 of the roll 1102 adjacent to the second part-interfacing surface1120 b of the horn 1110.

FIG. 12 is an illustration of a finite element analysis (FEA) of thehorn 1110 as synchronized ultrasonic energy is being transmitted by thedual transducers 1112 a, 1112 b into the horn 1110. The stresses andstrains of the metal of the horn 1110 cause it to expand and contractrapidly, which creates the scrubbing action, allowing the interfaces1120 a, 1120 b to move rapidly back and forth. This friction creates auniform heat energy that rapidly creates a hermetic seal on the roll intwo places simultaneously at the interfaces 1120 a, 1120 b. Thedistortion of the metal has been exaggerated in this model for ease ofillustration.

FIG. 13A is a perspective view of an ultrasonic-assisted “cut and seal”assembly 1300 having dual ultrasonic transducers 1312 a, 1312 b applyingsynchronized ultrasonic energy to a resonant horn 1310 that captures aroll, such as 1102, having multiple layers between the horn 1310 and ananvil 1314. FIG. 14A is a perspective view of an ultrasonic-assisted“cut and seal” assembly 1400 having dual ultrasonic transducers 1412 a,1412 b applying synchronized ultrasonic energy to a resonant horn 1410that captures a roll, such as 1102, having multiple layers between thehorn 1410 and an anvil 1414. Alternately, the horn 1310 can be driven bya single ultrasonic transducer in applications requiring a lower powerto weld but still benefiting from the horns scrubbing action. As can beseen by comparing FIGS. 13A and 14A, the resonant horn 1310 in FIG. 13Ahas short slots 1311, 1313 formed along an end edge of the horn 1310.The resonant horn with short slots near the output face as shown in FIG.13C has a node (region with minimal motion) near the interior side ofthe slots and an anti-node (region with maximum activity) on the outsidesurface of the horn. This motion creates a scrubbing action back andforth as shown in FIG. 13C. The resonant horn 1410 in FIG. 14A has longslots 1411 formed along a main body of the horn 1410, but otherwise theassemblies 1300, 1400 are the same. An optional blade 1316 is shown inthe anvil 1315, which can be used to carry out a cutting operation inthe space between adjacent sealed interfaces defined by the gap 1322between the fingers of the horn 1310 and the anvil 1314 as shown in FIG.13B. FIG. 13C illustrates two FEA images of the horn 1310 as theout-of-phase ultrasonic energy is applied by the dual transducers 1312a, 1312 b into the body of the horn 1310. The distortion or displacementof the horn 1310 has been exaggerated for ease of illustration, but theimages show how the horn 1310 moves rapidly back and forth in directionsof arrows A and B to create a scrubbing action on its end surfaces. Whenpressed against the anvil 1314, the combination of the scrubbing action,which produces heat contributed by the ultrasonic energy, and themechanical forces pressed against the film between the horn 1310 andanvil 1314, produces a hermetic seal at the film's interface where thescrubbing is carried out. This seal can be produced by actuating thehorn in and out or by rotating the horn continuously such that itcontacts the film twice per rotation.

FIG. 14B illustrates two FEA images of the resonant horn 1410 shown inFIG. 14A. Again, the distortions have been exaggerated to show thedirection of movement or distortion of the horn 1410 as the out-of-phaseultrasonic energy is passed through the body of the horn 1410 by thedual transducers 1412 a, 1412 b, which pass ultrasonic energy having asynchronized frequency toward one another into the horn 1410. The slots1411 become slightly distorted allowing the mechanical movement of thehorn 1410, which creates a rapid back-and-forth action referred toherein as scrubbing on the end surfaces of the horn 1410 where they arepressed against the anvil 1414. The horn 1410 may be actuated in and outor rotated continuously such that it contacts the film twice perrotation. The longer in FIG. 14B create a node (region of minimalactivity) and passes through the slots. The anti-node (region of maximummotion) occurs on the output face of the horn creating a scrubbingaction back and forth as shown in FIG. 14B.

FIG. 15A is a top or bottom view of a prior art cutting blade 1502sandwiched between two ultrasonic stack assemblies 1512 a, 1512 b. FIG.15B is a side view of the cutting blade 1502 and ultrasonic stackassemblies 1512 a, 1512 b shown in FIG. 15A. The cutting blade 1502 hastwo cutting edges 1524 a, 1524 b having a sharpness configured to cutthrough matter, such as a block of food. The type of matter isimmaterial to the present disclosure. A drawback to this prior artapproach is that the cutting blade 1502 suffers from multiple nodalpoints (areas of minimal motional activity) along the axis (and thecutting edges) of this blade 1502. As a result, there will be very poorcutting at and near those nodal points. The embodiments shown next inFIGS. 16-18 eliminate these undesirable nodal points along the cuttingedges and ensures a consistent amplitude along the cutting edges of thecutting blade. Moreover, the cutting blade 1502 shown in FIGS. 15A and15B is poorly suited to cut through materials having a thickness equalto or greater than a height of the cutting blade 1502.

FIG. 16A is a perspective view of a rotatable resonant cutting blade1602 of a synchronized cutting assembly 1600, which is sandwichedbetween two ultrasonic stack assemblies 1612 a, 1612 b whose respectivetransducers output synchronized ultrasonic energy (in frequency andphase) into the cutting blade 1602, which operates like a resonant horn.Alternately the horn shown in FIG. 16A can be driven by a singleultrasonic transducer in applications requiring a lower power. FIG. 16Bis a side view of the cutting blade assembly 1600 shown in FIG. 16A.FIG. 16C is an end view of the cutting blade assembly 1600 shown in FIG.16A. In this example, the cutting blade 1602 has long slots similar tothat shown in the horn 1110 of FIG. 11A and can be configured to rotateabout an axis running through the stacks 1612 a, 1612 b and the cuttingblade 1602. An example of this rotation is shown in FIGS. 17A-17C. Asthe cutting blade 1602 is cutting through matter, both stack assemblies1612 a, 1612 b introduce synchronized ultrasonic energy into the cuttingblade 1602 simultaneously, causing the blade 1602 to vibrate in apush-pull manner toward one stack 1612 a and away from the other stack1612 b, and vice versa. In addition to generating a consistent, evenamplitude along the cutting edges 1624 a, 1624 b of the cutting blade1602, the blade 1602 has the other advantage of being able to cutthrough material having a thickness that exceeds a height of the blade1602. An example of this embodiment is shown in FIG. 17 .

FIG. 17A is a perspective view of the rotatable cutting blade assembly1600 shown in FIG. 16A cutting through a thick block of matter 1700,such as food. FIG. 17B is an end view of the rotatable cutting bladeassembly 1600 shown in FIG. 17A in which the dual ultrasonic stackassemblies 1612 a, 1612 b are visible. FIG. 17C is a side view of therotatable cutting blade assembly 1600 shown in FIG. 17A. The entirecutting blade assembly 1600 together with the stacks 1612 a, 1612 b canbe configured to rotate about an axis running through the stacks 1612 a,1612 b and the blade 1602, which facilitates cutting through thickmatter, even thicknesses that exceed a height of the blade 1602. As theblade 1602, which is undergoing a push-pull vibration thanks to thesynchronized energies simultaneously applied by the stacks 1612 a, 1612b, slices or cuts through the matter 1700, the blade 1602 can be rotatedslightly to ensure that the cut is straight, and to accommodate thenon-flat contour of the blade 1602.

FIG. 18A is a functional illustration of a cutting blade 1602 that isconfigured to cut from a top or bottom cutting blade surface 1624 a,1624 b through matter 1800 having a thickness T1. In this example, T1 isless than a height of the blade 1602, and either cutting surface 1624 a,1624 b of the cutting blade 1602 can cut the matter 1800 as it issingulated into parts 1850 a, 1850 b, 1850 c, and so on.

FIG. 18B a functional illustration of a cutting blade 1602 that isconfigured to cut through matter 1802 having a thickness T2>>T1 and alsogreater than a height of the cutting blade 1602. This embodimentdemonstrates that the synchronized ultrasonic stacks herein can beleveraged to apply synchronized ultrasonic energy to a cutting bladehaving a height that is less than a thickness of the matter being cut toproduce singulated blocks of matter 1852 a, 1852 b, 1852 c, and so on.

FIG. 18C is a functional illustration showing how the cutting blade 1602can be rotated to cut a block of matter 1804 at least twice per completerotation of the cutting blade 1602, to produce singulated blocks ofmatter 1804 a, 1804 b, 1804 c. During the first half of the rotation,one of the cutting blade edges 1624 a cuts through the matter 1804, andduring the second half of a complete rotation, the other cutting bladeedge 1624 b cuts through the matter 1804. The thickness of the matter1804 is less than half of a height of the cutting blade 1602 to ensurethat the rotation of the blade 1602 does not interfere with the passingmatter 1804 moving relative to the blade 1602.

FIGS. 19A-19C, 20A-20C, and 21 illustrate different types of paddlehorns similar to those shown in FIGS. 12, 13A-13C, and 14A-14B. Becausethe paddle horns perform a “scrubbing” motion described above in whichthe entire surface in contact with the part(s) to be joined movesrapidly back and forth along a lateral direction (see arrows A and B inFIGS. 13C and 14B), the entire exposed edge or end surfaces of the hornon both sides is available for imparting ultrasonic energy into thepart(s) to be joined. The horns shown in FIGS. 12, 13A-13C, and 14A-14Balso share this advantage, namely, that the entire edge surface from oneend of the horn to the other is available for imparting ultrasonicenergy onto or into the part(s) to be joined. As a result, a much largerwelding area can be covered by the paddle horn, allowing longer orlarger parts to be joined, e.g., film attached to the top of acontainer, and when the paddle rotates, two welding cycles can beperformed in a single 360 degree rotation of the horn. No heat isrequired or applied to the weld interface, compared to conventionalsealing applications, because the ultrasonic energy is sufficient tojoin the parts together, e.g., a film to a container, or two filmswithout application of any heat energy. The paddle-shaped horns hereinallow the horn to expand and contract along its lateral dimension(orthogonal to its axis of rotation), creating a “scrubbing” movementalong the entire welding interface, as opposed to a “swelling” movementthat can be found in conventional applications. Such swelling movementsproduce a much smaller, and less reliable, weld area.

The paddle horns disclosed herein are particularly effective at sealinguneven film layers, e.g., when a total thickness of films to be joinedvaries along a length of the weld. Normally, using conventionalapplications, such uneven thickness would produce uneven welds; but withthe ultrasonic-driven paddle horns disclosed herein, the weld joints areuniform and hermetic.

The horn can be made of metal, and can be rigidly mounted to a fixedframe or structure, so that rotations of the horn are uniform and notsusceptible to wobble, allowing faster, consistent, and repeatably highquality welds for thousands and thousands of welds for many applicationsincluding packaging and non-woven applications.

FIGS. 19A and 19B illustrate two different paddle “cross seal” stylehorns 1910 having two elongated slots 1911 formed transverse to an axisof rotation of the paddle. The horn 1910 in FIG. 19A has multiplescaling protrusions 1936 whereas the horn 1910 in FIG. 19B has a singlescaling protrusion 1934 along edge surfaces of the horn 1910. Thescaling protrusion 1934 allow for welding multiple different types ofproducts using the same horn 1910, and can be designed so that the weldarea is much larger compared to traditional scrubbing-type horns.Ultrasonic energy is available across the entire length 1924 of the hornalong its axis of rotation, allowing for a welding large areas. Dualultrasonic boosters 1912 a, 1912 b, which are connected to correspondingultrasonic transducers (e.g., like transducers 2112 a, 2112 b shown inFIG. 21 ), apply the synchronized ultrasonic energy to the horn 1910 asdescribed above, which reaches the entire end or edge face of the horn1910 on both sides of the paddle parallel with the axis of rotation.FIG. 19C is an illustration of an exaggerated FEA analysis of the horn1910, showing how the slots 1911 allow the horn 1910 to expand andcontract laterally along its axis of rotation to create the back andforth scrubbing movement along the entire face edges of the horn 1910.The optional scaling protrusions 1934, 136 scale the welding surface asthe horn 1910 moves rapidly back and forth along the entire weldingsurface as ultrasonic energy is imparted throughout the horn 1910.

FIGS. 20A, 20B, and 20C are illustrations of exaggerated FEA analyses(for ease of discussion) of horns 2010 having different numbers of slots2011. The number of slots 2011 is commensurate with a length of the horn2010, such that the longer the horn, the more slots 2011 are formedalong its length as shown. In each case, welding is achieved along theentire length 2024 of the exposed face edges of the horn 2010. Dualultrasonic boosters 2012 a, 2012 b, which are connected to correspondingultrasonic transducers (e.g., like transducers 2112 a, 2112 b shown inFIG. 21 ), apply the synchronized ultrasonic energy to the horn 2010 asdescribed above, which reaches the entire end or edge face of the horn2010 on both sides of the paddle parallel with the axis of rotation.

FIG. 21 illustrates another style of paddle horn 2110 capable ofperforming a cross seal welding operation without use of heat to makethe weld with three keyhole-shaped slots 2111 having enlarged portions2113 to facilitate move lateral movement (along the direction of arrowsH) along the exposed edge surfaces 2130 a, 2130 b of the horn 2110. Dualultrasonic transducers coupled to corresponding ultrasonic boosters 2112a, 2112 b apply the synchronized ultrasonic energy to the horn 2110 asdescribed above, which reaches the entire end or edge face of the horn2110 on both sides of the paddle parallel with the axis of rotation toallow a uniform weld seal to be created on parts to be joined along theentire length of the end or edge face on both sides of the horn 2110.Alternately, if only one side is used for sealing, the other side can beused when the first side wears out. In this example, the horn would beflipped over 180 degrees so that unused side can be used to continuesealing, effectively doubling the operational lifetime of the hornbefore it needs to be serviced or machined.

The horns shown in FIGS. 13C, 14B, 16A, 19A-19C, 20A-20C, and 21described above produce a scrubbing motion thanks to design principlesthat will be discussed next. Ultrasonic horns are designed to have anatural resonance that is excited in operation. Many resonances exist ina structure of this size. A computer simulation can be used to tune thehorn structure to have a resonance with a desired motion direction anduniformity, while keeping any other undesired resonances more distant interms of frequency.

It should be noted that these resonances exist in the horn structureindependent of the booster and transducer attached to it. The purpose ofthe booster is to provide mechanical support, and, together with thetransducer, provide input vibrations to excite the aforementionednatural resonance. The booster and transducer have no substantialinfluence on the motion direction of the resonance, only on itsamplitude.

FIGS. 22 and 23 show two types of prior-art horns that use traditionalelongation resonance, where the direction of movement of the structureis designed to elongate the horn. Simple elongation-type ultrasonichorns have been utilized in industry for many years. In the FEA exampleof a prior-art vertically-oriented horn 2210 shown in FIG. 22 , thevertically-oriented horn 2210 has a height corresponding to a halfwavelength (λ/2) of the ultrasonic frequency applied and has a node 2252shown at the approximate central region (λ/4) of the horn 2210. A nodehere refers to a region of minimum or minimal amplitude and maximum ormaximal strain. Two anti-nodes 2250, 2254 appear at the top and bottomregions of the elongated horn. An anti-node is a region of maximumamplitude and minimum strain. As a result of the location of the node atthe mid-section and the anti-nodes at either end of the horn 2210, thehorn 2210 elongates along its length, moving in an up-and-down directionas shown in FIG. 22 , according to the frequency applied by theultrasonic transducer (not shown).

Similarly, FIG. 23 shows a prior-art, horizontally-oriented metalwelding horn 2310 having a length corresponding to one wavelength (1λ)of the applied ultrasonic frequency. Here, two nodes 2352, 2354 appearat approximately λ/4 and 3λ/4 along the length of the horn 2310, and twoanti-nodes 2356, 2358 are at the ends of the horn 2310, where it istypically fixed, e.g., to boosters or other fixed structures. Vibrationoccurs along section 2362, producing elongated movement of the horn 2310along its length. The elongated motions produced by the prior-art hornsshown in FIGS. 22 and 23 will not produce a scrubbing motion across thehorn's entire width (e.g., its longest dimension) as disclosed herein,but rather only in a much smaller, confined region.

Scrub-type horns using an elongational horn but contacting the sidecreate a scrubbing effect, such as the horns shown in FIGS. 13A through14B and FIGS. 19A through 21 . FIG. 24 illustrates an FEA analysis of ahorn 2400 like those shown above that produce a back-and-forth scrubbingaction. This horn 2400, which can be composed of a metal, includingtitanium, is a vertically-oriented horn having a height corresponding toone wavelength (1λ) of the applied ultrasonic frequency (e.g., 20 kHz).Example height dimensions include 4.6 inches per half wavelength(λ/2)+/−0.25 inches depending upon the overall configuration of thehorn. It should be emphasized that these dimensions are exemplary only,and those skilled in the art can appreciate how to adapt the dimensionsusing the teachings of the present disclosure based on the wavelengthand frequency of the applied ultrasonic energy. To produce the scrubbingeffect, two sets of nodes 2450, 2452 (regions of minimum or minimalamplitude and maximum or maximal strain) are arranged at each λ/4section along the height (1λ) of the horn 2400. By contrast, twoanti-nodes 2454, 2456 are arranged at either end 2430 a, 2430 b of thehorn 2400. The horn 2400 is fixed between points 2440, 2442, e.g., byrespective boosters (not shown). A single ultrasonic transducer (notshown) can drive the horn 2400 to produce the scrubbing action along theends 2430 a, 2430 b, thanks to the positions of the nodes 2450, 2452 andthe anti-nodes 2454, 2456, which cooperate to produce the scrubbingaction even with a single ultrasonic transducer.

Multiple slots 2411 can be formed along the length of the horn 2400, andthe number of slots can be related to the length of the horn 2400 asdescribed above.

For double-supported paddle-type horns, the choice of one versus twotransducers is based upon the required input power level. If twotransducers are used, the choice of push/push or push/pull is determinedby the motion designed into the horn, whereas in two horn applicationsthe push/push or push/pull can be chosen independently of the horn'sdesign. The two horn embodiment has unique advantages described in FIGS.2 through 3B above.

While some materials have been described herein as being suitable forsealing or welding using the synchronized dual-horn ultrasonic energyapplications disclosed herein, including plastic and non-woven film, thepresent disclosure contemplates sealing or welding other types of sameor dissimilar materials together, including pouches made from polyesterprinted to aluminum then laminated to polyethylene, metal includingaluminum, metal foil, fabric, film, polyethylene-coated fiberboard orliquid paperboard, and the like. The scrubbing motion or cross-seal andall other aspects herein are particularly well suited for mono-layerplastic films, PLA, bioplastics, biopolymers, biodegradable polymers orrecyclable materials, which are not particularly well-suited for heatsealing but seal very well when ultrasonic energy is applied at the sealinterface. Thinner layers can be sealed consistently and evenhermetically according to the aspects disclosed herein. By contrast,conventional heat sealing techniques can only be used on a few types offilms with specific width and thickness, where the minimum width is muchgreater than is possible with the ultrasonic techniques disclosedherein.

Advantages of the systems and methods disclosed herein include:

Process speed increase: compared to conventional ultrasonic weldingtechniques that require multiple cycles and applications of ultrasonicenergy, the systems and methods herein require only one cycle to createa hermetic seal for a variety of packaging, geometries, and materials.

Seal through same or dissimilar materials: a hermetic seal is formedthrough one application of synchronized ultrasonic energy impartedthrough two opposing horns, regardless of the material or its thicknessuniformity.

Consistency, repeatability in weld results with wider process windowparameters: Because two horns are applying the same ultrasonic energy(same frequency and phase) simultaneously, this effectively doubles theamplitude of the energy, enabling wider process window parameterscompared to conventional techniques.

Housekeeping in production area, greener process (ultrasonic weldingrequires a lot less energy than heat seal technology): compared toheat-seal technologies that require application of heat energy to createa seal, ultrasonic energy by comparison utilizes less energy, creating aseal in a fraction of a second, such as 0.35 seconds or even faster.

Enable use of new materials, including bioplastics and material withpoor welding compatibility: the dual horn setup synchronized tofrequency and phase, and optionally coupled with the scrubbing actionproduced by the vibrations of the horns, significantly expands theavailable combinations of materials, interfaces, and geometriesavailable for creating consistently high quality and hermetic seals orwelds.

Waste and delay reduction; yield improvements: conventional techniquesproduce inconsistent seals, sometimes with tiny leaks, or can createburns or other visual artifacts requiring that some parts be discarded,lowering overall yield.

Narrower seal producing material savings: the interface or area to besealed can be quite small compared to conventional techniques, allowingless overall material to be used. When millions of parts are beingsealed or welded, a small reduction in material per part can yield asignificant reduction in overall material.

Eliminate channel leaking: conventional techniques can produce tinyleaks that can create opportunities for air, pathogens, and/or mold tobe present, but systems and methods of the present disclosure eliminateleaks without creating any visual artifacts and without causing burns atthe interface of the seal. This can extend the shelf life of productinside the package/container, which allows product to be shipped fartherover longer distance. Compared to thermal sealing, the ultrasonictechniques herein reduce leakage rate from 1.5% to about 0.87-0.50%,saving millions of packages annually, reducing landfill waste.

Reducing manufacturing process complexity as for example welding spoutto pouches can be done in one pass or cycle with this technology. Bycomparison, the same spout-to-pouch welding is currently being carriedout in three passes or cycles with conventional ultrasonic weldingtechnology.

Eliminate liquid or product contamination in the joint area due toultrasonic energy (vibrations) from the ultrasonic stacks. It can alsoeliminate liquid content between two joints on vertical or horizontalpackaging machines, where liquid is not desirable (e.g., in a brickcarton assembly line).

Unlike heat sealing, ultrasonic sealing produces heat only inside theseal, and not beyond. For applications such as wet food containingproteins and sugary drinks in pouches, for example, or salad or powderyproducts, it is important not to introduce thermal energy into thecontents during the sealing process. Ultrasonic energy using the aspectsdisclosed herein prevent thermal impingement into the product contents.In ultrasonic sealing, the sealing layers bond together at a molecularlayer before any undesirable heat conduction can be disseminated intothe package contents or material. Using the ultrasonic techniquesherein, packaging can be closed much more “gently” for the type ofpackaging and feed material. Shrinkage and leakage are minimized or allbut eliminated altogether. The vibrational movements of the ultrasonictechniques herein can also advantageously vibrate potential contaminantsaway from the seal area. This is not possible with conventional thermalapplications.

Moreover, many more highly accurate and digital parameter controloptions are available using the ultrasonic techniques disclosed herein.Whereas heat seal applications allow temperature, pressure, and timesettings to be adjusted; the ultrasonic applications disclosed hereinhave the following parameters that can be adjusted with extremeprecision, and using digital control: operating frequency, toolamplitude, weld mode (time, energy, or by collapse distance), velocity,trigger force, seal force, hold time, reject limits, and dataacquisition for quality assurance, traceability, and regulatoryrequirements.

As mentioned above, the ultrasonic embodiments disclosed herein producea smaller package size, a smaller seal width, and therefore materialsavings for each package. The following Table 1 illustrates one exampleof such savings:

TABLE 1 Package 1: Package 2: Heated Tooling Seals Ultrasonic SealsOverall package height 6.0″ 5.25″ Width per seal (×2) 0.50″ (1.00″)0.125″ (0.25″) Internal package height 5.0″ 5.0″ Production rate 24million 24 million Material savings/pkg N/A 0.75″ Net material savings24 million × 0.75″/ 36~500,000 yards per year

The following Table 2 shows total power savings, reducing the carbonimpact using the ultrasonic embodiments disclosed herein:

TABLE 2 Heat Seal Ultrasonic Seal Seal rate/min 100 100 Consumption W/hr4 × 500 W cartridge 1,500 W power supply = heaters = 2000 W/hr 1,500W/hr max. with continuous operation; ~500 W/hr max in non-continuousoperation Total consumption 32,000 W/day 24,000 W/day-continuous (W × 16hr) operation 500 W/day-non-continuous operation Savings 25-75%depending on the application and operating time

The ultrasonic embodiments disclosed herein are particularly well-suitedfor mono-materials or materials with a mono-layer as opposed to multiplelayers. However, mono-materials are more susceptible to film shrinkagedue to mechanically and thermally less stable support layers. Thesealing seam appearance can suffer as a result. Ultrasonic sealingcounteracts this due to cold tools, which has a in turn a positiveeffect on downtimes and the need for wear materials such ashigh-temperature Teflon tapes used in some conventional applications.Ultrasonic energy is only needed during the sealing time, so there is noneed to have high standby power consumption as with conventional thermalsealing processes. The tools in the ultrasonic applications are readyfor immediate use without having to heat up first.

Referring to FIG. 25 , an ultrasonic welding system 2500 according tosome implementations of the present disclosure is illustrated. Thesystem 2500 includes a first horn 2510, a second horn 2530, a pluralityof transducers 2550A-2530D, a plurality of boosters 2560A-2560D, acontroller 2570, and a memory 2580. As described herein, the system 2500can be used to ultrasonically weld one or more parts (e.g., any of theexemplary parts described herein).

The first horn 2510 and the second 2530 are the same as, or similar to,other horns (e.g., the horn 1410) described herein. The first horn 2510and the second horn 2530 can be rotated 360 degrees about theirrespective longitudinal axes (e.g., via one or more motors or actuators)such that a part to be welded can pass between the first horn 2510 andthe second horn 2530 and contacts or engages respective part-interfacingsurfaces of the first horn 2510 and the second horn 2530. Thetransducers 2550A-2550D impart ultrasonic energy to the first horn 2510and the second horn 2530 so that the respective part-interfacingsurfaces vibrate back and forth in a scrubbing motion to form a weld asthe part passes between the respective part-interfacing surfaces of thefirst horn 2510 and the second horn 2530. This ultrasonic energy can beimparted during rotation of the first horn 2510 and the second horn2530.

The plurality of slots 2516A-2516B are formed along a major surface ofthe first horn 2510 and are the same as, or similar to, the slots 1411described above (FIGS. 14A-14B). The plurality of apertures 2518A-2518Dare also formed along the same major surface of the first horn 2510.During a welding operation, the plurality of slots 2516A-2516B and theplurality of apertures 2518A-2518D become slightly distorted allowingthe mechanical movement of the horn 2510, which creates a rapidback-and-forth action described herein as scrubbing on the firstpart-interfacing surface 2512 and the second part-interfacing surface2514 of the first horn 2510.

Referring to FIGS. 26A-26B, the first horn 2510 includes a firstpart-interfacing surface 2512, a second part-interfacing surface 2514, aplurality of slots 2516A-2516B, and a plurality of apertures2518A-2518D. As described herein, the first part-interfacing surface2512 and the second part-interfacing surface 2514 vibrate back and forthalong their lengths in response to ultrasonic energy being imparted tothe first horn 2510 (e.g., via the first transducer 2550A, the secondtransducer 2550B, or both). The first part-interfacing surface 2512 andthe second part-interfacing surface 2514 also rotate about alongitudinal axis of the first horn 2510 as the first horn 2510 isrotated. For example, both the first part-interfacing surface 2512 andthe second part-interfacing surface 2514 can contact a part or material(e.g., a film) during a single rotation (360 degrees about thelongitudinal axis) of the first horn 2510.

As shown in FIG. 26B, the first part-interfacing surface 2512 of thefirst horn 2510 includes a first part-contacting portion 2520A and asecond part-contacting portion 2520B that aid the first horn 2510 inengaging a part to be welded. As the first horn 2510 rotates, the firstpart-contacting portion 2520A and the second part-contacting portion2520B will contact the part to be welded and pull or urge the partgenerally in the direction that the first horn 2510 is rotating. Thefirst part-contacting 2520A and the second part-contacting portion 2520Bare each curved or angled (e.g., as opposed to being straight or havingright angles) to aid in engaging the part to be welded. In other words,the curved or angled profile aids in engaging (e.g., squeezing) the partto be welded in a more gradual matter than if these portions were formedat right angles. This is especially advantageous for welding relativelythin materials, which can potentially deform, rip, or tear whencontacting first horn 2510. The angle of the first part-contacting 2520Aand the second part-contacting portion 2520B can be, for example,between about 1 degree and about 5 degrees.

The second horn 2530 is the same as, or similar to, the first horn 2510described herein. As shown in FIG. 27 , the second horn 2530 includes afirst part-interfacing surface 2532 and a second part-interfacingsurface 2534, which are the same as, or similar to, the firstpart-interfacing surface 2512 and the second part-interfacing surface2514 of the first horn 2510. The first part-interfacing surface 2532 andthe second part-interfacing surface 2534 of the second horn 2530 canhave the same or similar curved or angled part-contacting parts as thosedescribed above for the first horn 2510.

Referring back to FIG. 25 , the plurality of transducers 2550A-2530B arethe same as, or similar to, the other transducers described herein andimpart ultrasonic energy to the first horn 2510 and the second horn2530. Specially, in the example shown in FIG. 25 , the first transducer2550A and the third transducer 2550C impart ultrasonic energy to thefirst horn 2510, while the second transducer 2550B and the fourthtransducer 2550D impart ultrasonic energy to the second horn 2530. Thefirst transducer 2550A is positioned on or adjacent to a first end ofthe first horn 2510 and the third transducer 2550C is positioned on oradjacent to a second, opposing end of the first horn 2510. Similarly,the second transducer 2550B is positioned on or adjacent to a first endof the second horn 2530 and the fourth transducer 2550D is positioned onor adjacent to a second, opposing end of the second horn 2530.

The plurality of boosters 2560A-2560D are the same as, or similar to,the other boosters described herein and amplify the ultrasonic energyimparted by the plurality of transducers 2550A-2550D. In the exampleshown in FIG. 25 , the first booster 2560A is positioned between thefirst transducer 2550A and the first horn 2510, the second booster 2560Bis positioned between the second transducer 2550B and the second horn2530, the third booster 2560C is positioned between the third transducer2550C and the first horn 2510, and the fourth booster 2560D ispositioned between the fourth transducer 2550D and the first horn 2510.

While the system 2500 is shown in FIG. 25 as including each of the firsttransducer 2550A, the second transducer 2550B, the third transducer2550C, the fourth transducer 2550D, the first booster 2560A, the secondbooster 2560B, the third booster 2560C, and the fourth booster 2560D,one or more alternative systems including less than four transducersand/or less than four boosters can be formed. For example, a firstalternative system can include the first transducer 2550A and the secondtransducer 2550B, but does not include the third transducer 2550C, thefourth transducer 2550D, the first booster 2560A, the second booster2560B, the third booster 2560C, or the fourth booster 2560D. In thisfirst alternative system, the first horn 2510 is coupled directly to thefirst transducer 2550A and the second horn 2530 is coupled directly tothe second transducer 2550B. As another example, a second alternativesystem can include the first transducer 2550A, the second transducer2250B, the first booster 2560A, and the second booster 2560B, but doesnot include the third transducer 2550C, the fourth transducer 2550D, thethird booster 2560C, or the fourth booster 2560D. As another example, athird alternative system can include the first transducer, the secondtransducer, the third transducer, and the fourth transducer, but doesnot include the first booster, the second booster, the third booster,and the fourth booster.

The controller 2570 includes one or more processors 2572. The controller2570 is generally used to control (e.g., actuate) the various componentsof the system 2500 (e.g., the transducers 2550A-2550D) and/or analyzedata obtained and/or generated by the components of the system 2500. Theprocessor 2572 can be a general or special purpose processor ormicroprocessor. The controller 2570 can include any number of processors(e.g., one processor, two processors, five processors, ten processors,etc.) that can be in a single housing, or located remotely from eachother. The controller 2570 (or any other control system) or a portion ofthe controller 2570 such as the processor 2572 (or any otherprocessor(s) or portion(s) of any other control system), can be used tocarry out one or more steps of any of the methods described and/orclaimed herein. The controller 2570 can be centralized (within one suchhousing) or decentralized (within two or more of such housings, whichare physically distinct). In such implementations including two or morehousings containing the controller 2570, such housings can be locatedproximately and/or remotely from each other.

The memory 2580 stores machine-readable instructions that are executableby the processor 2572 of the controller 2570. The memory 2580 can be anysuitable computer readable storage device or media, such as, forexample, a random or serial access memory device, a hard drive, a solidstate drive, a flash memory device, etc. The system 2500 can include anysuitable number of memory devices (e.g., one memory device, two memorydevices, five memory devices, ten memory devices, etc.). Like thecontroller 2570, the memory 2580 can be centralized (within one suchhousing) or decentralized (within two or more of such housings, whichare physically distinct).

As described herein, the controller 2570 can, among other things, causethe plurality of transducers 2550A-2550D to impart ultrasonic energy tothe first horn 2510 and the second horn 2530 can cause the respectivepart-interfacing surfaces to vibrate back and forth in the same ordifferent directions. Referring to FIG. 27 , the controller 2570 cancause the first horn 2510 and the second horn 2530 to move, for example,in the direction of arrow A, the direction or arrow B, or both. In someimplementations, the controller 2570 causes the first horn 2510 to movein the direction of arrow A and, simultaneously (e.g., both at a firsttime), the second horn 2530 to move in the direction of arrow B. Asshown, the direction of arrow A is opposite the direction of arrow B.The controller 2570 can then cause the first horn 2510 to move in thedirection of arrow B and, simultaneously (e.g., both at a second timesubsequent to the first time), the second horn 2530 to move in thedirection of arrow A. This series movements by the first horn 2510 andthe second horn 2530 can be repeated one or more times. In suchimplementations, the movement of the first horn 2510 and the second horn2530 can be considered out of phase.

In other implementations, the controller 2570 causes both the first horn2510 and the second horn 2530 to move in the direction of arrow Asimultaneously (e.g., at a first time). In other words, in suchimplementations, the first horn 2510 and the second horn 2530 move inthe same direction. In such implementations, the controller 2570 canalso cause both the first horn 2510 and the second horn 2530 to move inthe direction of arrow B simultaneously (e.g., at a second timesubsequent to the first time), and then repeat this series of movementsone or more times. The movement of the first horn 2510 and the secondhorn 2530 in such implementations can be considered in phase.

In some implementations, the controller 2570 controls the frequency ofthe first ultrasonic energy imparted to the first horn 2510, the phaseof the first ultrasonic energy imparted to the first horn 2510, thefrequency of the second ultrasonic energy imparted to the second horn2530, the phase of the second ultrasonic energy imparted to the secondhorn 2530, or any combination thereof.

In a first exemplary implementation, the controller 2570 causes thefrequency of the first ultrasonic energy applied to the first horn 2510to match the frequency of the second ultrasonic energy applied to thesecond horn 2530 while the respective ultrasonic are out of phase. Inthis example, the matching or synchronized frequencies are the same(e.g., both frequencies are about 20 kHz) or substantially the same(e.g., both frequencies are within about ±2 Hz of one another). Thephase of the first ultrasonic energy imparted to the first horn 2510 is180 degrees out of phase with the phase of second ultrasonic energyimparted to the second horn 2530. When the applied ultrasonic energiesare out of phase, the first horn 2510 and the second horn 2530 move inopposite directions (e.g., the first horn 2510 moves in a firstdirection while the second horn 2530 moves in a second direction that isopposite the first direction). Using two horns (e.g., the first horn2510 and the second horn 2530) is advantageous compared to using onehorn and an anvil because, for example, when the first horn 2510 and thesecond horn 2530 are out of phase, this doubles the amplitude of theultrasonic power applied to the part to be welded compared to a casewhere only one horn was used.

In a second exemplary implementation, the controller 2570 causes thefrequency and phase of the first ultrasonic energy applied to the firsthorn 2510 to match the frequency and phase of the second ultrasonicenergy applied to the second horn 2530. The matching frequencies are thesame (e.g., both frequencies are about 20 kHz) or substantially the same(e.g., both frequencies are within about ±2 Hz). When the phases of theapplied ultrasonic energies match, the movement of the first horn 2510and the second horn 2530 is synchronized (e.g., the first horn 2510 andthe second horn 2530 move in the same direction at the same time).

In a third exemplary implementation, the controller 2570 controls thefrequency and phase of the first ultrasonic energy applied to the firsthorn 2510 and, independently, the frequency and phase of the secondultrasonic energy applied to the second horn 2530. For example, thecontroller 2570 can cause the ultrasonic frequencies for both horns tobe substantially the same or similar (e.g., both frequencies are within±500 Hz). In one example, both frequencies are maintained at about 20kHz. While the phases are independent of each other (e.g., they are notcaused to either be matched or 180 degrees out of phase), the effectiveamplitude applied to the part to be welded is greater than the amplitudeif only a single ultrasonic horn were used in the welding operation(e.g., the amplitude is about 1.4 times greater than the amplitude ifonly one of the first horn 2510 and second horn 2530 were used with ananvil).

In a fourth exemplary implementation, the controller 2570 causes thefrequency and phase of the first ultrasonic energy applied to the firsthorn 2510 to be substantially different than the frequency and phase ofthe second ultrasonic energy applied to the second horn 2530. In onenon-limiting example, the frequency of the first ultrasonic energy forthe first horn 2510 is about 20 kHz and the frequency of the secondultrasonic energy for the second horn 2530 is about 35 kHz.

While each of the first, second, third, and fourth exemplaryimplementations above have been described as using controller 2570, itshould be understood that multiple controllers are the same as, orsimilar to, the controller 2570 can be used in such implementations. Forexample, in the third and fourth exemplary implementations, a firstcontroller can be used for the first horn while a second controller isused for the second horn.

Referring to FIG. 28 , a method 2800 for welding a part according tosome implementations of the present disclosure is illustrated. One ormore steps or aspects of the method 2800 can be implemented using anyelement or aspect of the system 2500 described herein.

Step 2801 includes causing a first transducer to impart a firstultrasonic energy to a first horn to cause a first part-interfacingsurface of the first horn to vibrate back and forth along its length.For example, the controller 2570 can cause the first transducer 2550A,the third transducer 2550C, or both to impart a first ultrasonic energyto the first horn 2510. The first ultrasonic energy can have a firstfrequency that is controlled by the controller 2570.

Step 2802 includes causing a second transducer to impart a secondultrasonic energy to a second horn to cause the second part-interfacingsurface of the second horn to vibrate back and forth along its length.For example, the controller 2570 can cause the second transducer 2550B,the fourth transducer 2550D, or both to impart a second ultrasonicenergy to the second horn 2530. The second ultrasonic energy can have asecond frequency that is controlled by the controller 2570.

Step 2803 includes causing a part to be welded to move between the firstpart-interfacing surface of the first horn and the secondpart-interfacing surface of the second horn. For example, the controller2570 can cause a part to be welded (e.g., a film) to pass between thefirst part-interfacing surface 2512 of the first horn 2510 and thesecond part-interfacing surface 2532 of the second horn 2530.Alternatively, the controller 2570 can cause the part to be welded topass between the second part-interfacing surface 2514 of the first horn2510 and the second part-interfacing surface 2534 of the second horn2530. Step 2803 can occur before, after, or at the same time as one orboth of step 2801 and step 2802.

Step 2804 includes causing the first horn to move in a first directionrelative to the part to be welded at a first time. For example, thecontroller 2570 can cause the first horn 2510 to move in the firstdirection relative to the part to be welded. Step 2804 can occur before,after, or simultaneously with step 2801.

Step 2805 includes causing the second horn to move in a second directionrelative to a part to be welded at the first time. As described herein,the second direction can be, for example, either (1) different (e.g.,opposite) the first direction (out of phase) or (2) the same as thefirst direction (in phase). Step 2805 can occur before, after, orsimultaneously with one or both of step 2804 and step 2802.

The method 2800 can also include causing the first horn and the secondhorn to rotate about their respective longitudinal axes. For example,the controller 2570 can cause the first horn to rotate at a firstrotational speed and the second horn to rotate at a second rotationalspeed (e.g., via one or more motors or actuators). The first rotationalspeed and the second rotational speed can be the same or different.

One or more steps of the method 2800 can be repeated one or more timesto perform multiple welds. For example, the method 2800 can be repeatedsuch that as a film passes between the first horn at the second horn, arespective part-interfacing surface of each horn contacts the film twicefor each rotation of the first horn and the second horn.

Referring to FIG. 29 , illustrates an FEA analysis of a horn 2910 likethose shown above that produce a back-and-forth scrubbing action. Inthis example, the horn 2910 includes a first anti-node 2920A positionedat a first end of the horn 2910 (e.g., where ultrasonic energy isimparted to the horn 2910), a second anti-node 2920B at a second,opposing end of the horn 2910, a third anti-node 2920C on a firstpart-interfacing surface of the horn 2910, a fourth anti-node 2920D on asecond part-interfacing surface of the horn 2910 that is opposite thefirst part-interfacing surface, and anti-nodes 2920E-29201.Additionally, nodes 2930A-2930J are positioned at various locationsalong the horn 2910. Specifically, nodes 2930A-2930E are positionedbetween the first part-interfacing surface and the center longitudinalaxis of the horn 2910, while nodes 2930F-2930J are positioned betweenthe second part-interfacing surface and the center longitudinal axis ofthe horn 2910. As described herein, the anti-nodes are locations wherethe amplitude of the ultrasonic energy is at or near the greatest in thehorn 2910 during operation. By contrast, the nodes are locations werethe amplitude of the ultrasonic energy is at or near the lowest in thehorn 2910 during operation.

While the present disclosure has been described with reference to one ormore particular embodiments or implementations, those skilled in the artwill recognize that many changes may be made thereto without departingfrom the spirit and scope of the present disclosure. Each of theseimplementations and obvious variations thereof is contemplated asfalling within the spirit and scope of the present disclosure. It isalso contemplated that additional implementations according to aspectsof the present disclosure may combine any number of features from any ofthe implementations described herein.

What is claimed is:
 1. A system comprising: a first horn including afirst part-interfacing surface; a first ultrasonic transducer configuredto impart ultrasonic energy into the first horn; a second horn includinga second part-interfacing surface, the second horn being positionedrelative to the first horn such that a part to be welded can bepositioned between the first part-interface surface and the secondpart-interfacing surface; a second ultrasonic transducer configured toimpart ultrasonic energy into the second horn; a memory storingmachine-readable instructions; and a controller including one or moreprocessors configured to execute the machine-readable instructions to:cause a first ultrasonic energy to be applied through the first horn viathe first transducer to cause the first part-interfacing surface tovibrate back and forth along its length; cause the first horn to move ina first direction at a first time relative to the part to be welded;cause a second ultrasonic energy to be applied through the second hornvia the second transducer to cause the second part-interfacing surfaceto vibrate back and forth along its length; and cause the second horn tomove in a second direction at the first time relative to the part to bewelded.
 2. The system of claim 1, wherein the first part-interfacingsurface of the first horn includes a first curved part-contactingportion and a second curved part-contacting portion, the first curvedpart-contacting portion and the second curved part-contacting portionbeing configured to aid the first part-interfacing surface in engagingthe part to be welded.
 3. The system of claim 1, wherein the firstpart-interfacing surface of the first horn includes a firstpart-contacting portion having a first angle and a secondpart-contacting portion having a second angle, the first part-contactingportion and the second part-contacting portion being configured to aidthe first part-interfacing surface in engaging the part to be welded. 4.The system of claim 3, wherein the first angle and the second angle arebetween about 1 degree and about 5 degrees.
 5. The system of claim 1,wherein the first direction is different than the second direction. 6.The system of claim 5, wherein the first direction is opposite to thesecond direction.
 7. The system of claim 5, wherein the control systemis further configured to cause the first horn to move in the seconddirection at a second time subsequent to the first time; and cause thesecond horn to move in the first direction at the second time.
 8. Thesystem of claim 1, wherein the first direction is the same as the seconddirection.
 9. The system of claim 8, wherein the control system isfurther configured to cause the first horn and the second horn to movein a third direction at a second time subsequent to the first time. 10.The system of claim 1, wherein the controller is configured to cause thefirst ultrasonic energy to have a first frequency and a first phase andthe second ultrasonic energy to have a second frequency and a secondphase.
 11. The system of claim 10, wherein the first frequency is thesame as the second frequency and the first phase is the same as thesecond phase.
 12. The system of claim 10, wherein the first frequency isthe same as the second frequency and the first phase is different thanthe second phase.
 13. The system of claim 10, wherein the firstfrequency is different than the second frequency and the first phase isdifferent than the second phase.
 14. The system of claim 13, wherein thefirst frequency and the second frequency are about 20 kHz, and whereinthe first ultrasonic energy has a first phase and the second ultrasonicenergy has a second phase that does not match the first phase.
 15. Thesystem of claim 13, wherein the first frequency is about 20 kHz and thesecond frequency is about 35 kHz, and wherein the first ultrasonicenergy has a first phase and the second ultrasonic energy has a secondphase that does not match the first phase.
 16. The system of claim 1,further comprising: a first booster positioned between the first hornand the first ultrasonic transducer; and a second booster positionedbetween the second horn and the second ultrasonic transducer.
 17. Thesystem of claim 18, further comprising: a third ultrasonic transducerconfigured to configured to impart ultrasonic energy into the firsthorn; and a fourth ultrasonic transducer configured to configured toimpart ultrasonic energy into the second horn.
 18. The system of claim17, further comprising: a third booster positioned between the firsthorn and the third ultrasonic transducer; and a fourth boosterpositioned between the second horn and the fourth ultrasonic transducer.19. The system of claim 1, further comprising: a third ultrasonictransducer configured to configured to impart ultrasonic energy into thefirst horn; and a fourth ultrasonic transducer configured to configuredto impart ultrasonic energy into the second horn.
 20. The system ofclaim 1, wherein the first horn includes a plurality of slots formedalong a major surface of the first horn, and wherein the second hornincludes a plurality of slots formed along a major surface of the secondhorn, each of at least some of the slots having a length running in atransverse direction to the length to facilitate the movements of thefirst horn and the second horn, respectively.
 21. The system of claim 1,wherein the first horn includes a third part-interfacing surfaceopposite the first part-interfacing surface and the second horn includesa fourth part-interfacing surface opposite the second part-interfacingsurface, wherein the first ultrasonic energy causes the thirdpart-interfacing surface to vibrate back and forth along its length andthe second ultrasonic energy causes the fourth part-interfacing surfaceto vibrate back and horn along its length, and wherein the controller isfurther configured to cause the first horn to rotate about itslongitudinal axis and cause the second horn to rotate about itslongitudinal axis such that the part to be welded passes between thefirst part-interface surface and the second part-interfacing surface orbetween the third part-interface surface and the fourth part-interfacingsurface.
 22. The system of claim 1, wherein the controller is furtherconfigured to cause the first horn and the second horn to rotate whilethe first ultrasonic energy is applied to the first horn and the secondultrasonic energy is applied to the second horn.